diff --git a/BTCPayServer/Controllers/InvoiceController.cs b/BTCPayServer/Controllers/InvoiceController.cs
index c4eba1e73..d86a4f862 100644
--- a/BTCPayServer/Controllers/InvoiceController.cs
+++ b/BTCPayServer/Controllers/InvoiceController.cs
@@ -175,6 +175,8 @@ namespace BTCPayServer.Controllers
                 excludeFilter = PaymentFilter.Where(p => !supportedTransactionCurrencies.Contains(p));
             }
             entity.PaymentTolerance = invoice.Checkout.PaymentTolerance ?? storeBlob.PaymentTolerance;
+            if (additionalTags != null)
+                entity.InternalTags.AddRange(additionalTags);
             return await CreateInvoiceCoreRaw(entity, store, excludeFilter, cancellationToken);
         }
 
diff --git a/BTCPayServer/Controllers/StoresController.Integrations.cs b/BTCPayServer/Controllers/StoresController.Integrations.cs
new file mode 100644
index 000000000..6230d549b
--- /dev/null
+++ b/BTCPayServer/Controllers/StoresController.Integrations.cs
@@ -0,0 +1,264 @@
+using System;
+using System.Collections.Generic;
+using System.Globalization;
+using System.IO;
+using System.Linq;
+using System.Net.Http;
+using System.Threading.Tasks;
+using BTCPayServer.Client.Models;
+using BTCPayServer.Data;
+using BTCPayServer.Models.StoreViewModels;
+using BTCPayServer.Services.Invoices;
+using BTCPayServer.Services.Shopify;
+using BTCPayServer.Services.Shopify.ApiModels;
+using BTCPayServer.Services.Shopify.Models;
+using BTCPayServer.Services.Stores;
+using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Cors;
+using Microsoft.AspNetCore.Mvc;
+using Newtonsoft.Json.Linq;
+using NicolasDorier.RateLimits;
+
+namespace BTCPayServer.Controllers
+{
+    public partial class StoresController
+    {
+        private static string _cachedShopifyJavascript;
+
+        private async Task<string> GetJavascript()
+        {
+            if (!string.IsNullOrEmpty(_cachedShopifyJavascript) && !_BTCPayEnv.IsDeveloping)
+            {
+                return _cachedShopifyJavascript;
+            }
+
+            string[] fileList = _BtcpayServerOptions.BundleJsCss
+                ? new[] {"bundles/shopify-bundle.min.js"}
+                : new[] {"modal/btcpay.js", "shopify/btcpay-shopify.js"};
+
+
+            foreach (var file in fileList)
+            {
+                await using var stream = _webHostEnvironment.WebRootFileProvider
+                    .GetFileInfo(file).CreateReadStream();
+                using var reader = new StreamReader(stream);
+                _cachedShopifyJavascript += Environment.NewLine + await reader.ReadToEndAsync();
+            }
+
+            return _cachedShopifyJavascript;
+        }
+
+        [AllowAnonymous]
+        [HttpGet("{storeId}/integrations/shopify/shopify.js")]
+        public async Task<IActionResult> ShopifyJavascript(string storeId)
+        {
+            var jsFile =
+                $"var BTCPAYSERVER_URL = \"{Request.GetAbsoluteRoot()}\"; var STORE_ID = \"{storeId}\"; {await GetJavascript()}";
+            return Content(jsFile, "text/javascript");
+        }
+
+        [RateLimitsFilter(ZoneLimits.Shopify, Scope = RateLimitsScope.RemoteAddress)]
+        [AllowAnonymous]
+        [EnableCors(CorsPolicies.All)]
+        [HttpGet("{storeId}/integrations/shopify/{orderId}")]
+        public async Task<IActionResult> ShopifyInvoiceEndpoint(
+            [FromServices] InvoiceRepository invoiceRepository,
+            [FromServices] InvoiceController invoiceController,
+            [FromServices] IHttpClientFactory httpClientFactory,
+            string storeId, string orderId, decimal amount, bool checkOnly = false)
+        {
+            var invoiceOrderId = $"{ShopifyOrderMarkerHostedService.SHOPIFY_ORDER_ID_PREFIX}{orderId}";
+            var matchedExistingInvoices = await invoiceRepository.GetInvoices(new InvoiceQuery()
+            {
+                OrderId = new[] {invoiceOrderId}, StoreId = new[] {storeId}
+            });
+            matchedExistingInvoices = matchedExistingInvoices.Where(entity =>
+                    entity.GetInternalTags(ShopifyOrderMarkerHostedService.SHOPIFY_ORDER_ID_PREFIX)
+                        .Any(s => s == orderId))
+                .ToArray();
+
+            var firstInvoiceStillPending =
+                matchedExistingInvoices.FirstOrDefault(entity => entity.GetInvoiceState().Status == InvoiceStatus.New);
+            if (firstInvoiceStillPending != null)
+            {
+                return Ok(new
+                {
+                    invoiceId = firstInvoiceStillPending.Id,
+                    status = firstInvoiceStillPending.Status.ToString().ToLowerInvariant()
+                });
+            }
+
+            var firstInvoiceSettled =
+                matchedExistingInvoices.LastOrDefault(entity =>
+                    new[] {InvoiceStatus.Paid, InvoiceStatus.Complete, InvoiceStatus.Confirmed}.Contains(
+                        entity.GetInvoiceState().Status));
+
+            var store = await _Repo.FindStore(storeId);
+            var shopify = store?.GetStoreBlob()?.Shopify;
+            ShopifyApiClient client = null;
+            ShopifyOrder order = null;
+            if (shopify?.IntegratedAt.HasValue is true)
+            {
+                client = new ShopifyApiClient(httpClientFactory, shopify.CreateShopifyApiCredentials());
+                order = await client.GetOrder(orderId);
+                if (string.IsNullOrEmpty(order?.Id))
+                {
+                    return NotFound();
+                }
+            }
+
+            if (firstInvoiceSettled != null)
+            {
+                //if BTCPay was shut down before the tx managed to get registered on shopify, this will fix it on the next UI load in shopify
+                if (client != null && order?.FinancialStatus == "pending" &&
+                    firstInvoiceSettled.Status != InvoiceStatus.Paid)
+                {
+                    await new OrderTransactionRegisterLogic(client).Process(orderId, firstInvoiceSettled.Id,
+                        firstInvoiceSettled.Currency,
+                        firstInvoiceSettled.Price.ToString(CultureInfo.InvariantCulture), true);
+                    order = await client.GetOrder(orderId);
+                }
+
+                if (order?.FinancialStatus != "pending" && order?.FinancialStatus != "partially_paid")
+                {
+                    return Ok(new
+                    {
+                        invoiceId = firstInvoiceSettled.Id,
+                        status = firstInvoiceSettled.Status.ToString().ToLowerInvariant()
+                    });
+                }
+            }
+
+            if (checkOnly)
+            {
+                return Ok();
+            }
+
+            if (shopify?.IntegratedAt.HasValue is true)
+            {
+                if (string.IsNullOrEmpty(order?.Id) ||
+                    !new[] {"pending", "partially_paid"}.Contains(order.FinancialStatus))
+                {
+                    return NotFound();
+                }
+
+                //we create the invoice at due amount provided from order page or full amount if due amount is bigger than order amount
+                var invoice = await invoiceController.CreateInvoiceCoreRaw(
+                    new CreateInvoiceRequest()
+                    {
+                        Amount = amount < order.TotalPrice ? amount : order.TotalPrice,
+                        Currency = order.Currency,
+                        Metadata = new JObject {["orderId"] = invoiceOrderId}
+                    }, store,
+                    Request.GetAbsoluteUri(""), new List<string>() {invoiceOrderId});
+
+                return Ok(new {invoiceId = invoice.Id, status = invoice.Status.ToString().ToLowerInvariant()});
+            }
+
+            return NotFound();
+        }
+
+
+        [HttpGet]
+        [Route("{storeId}/integrations")]
+        [Route("{storeId}/integrations/shopify")]
+        public IActionResult Integrations()
+        {
+            var blob = CurrentStore.GetStoreBlob();
+
+            var vm = new IntegrationsViewModel {Shopify = blob.Shopify};
+
+            return View("Integrations", vm);
+        }
+
+        [HttpPost]
+        [Route("{storeId}/integrations/shopify")]
+        public async Task<IActionResult> Integrations([FromServices] IHttpClientFactory clientFactory,
+            IntegrationsViewModel vm, string command = "", string exampleUrl = "")
+        {
+            if (!string.IsNullOrEmpty(exampleUrl))
+            {
+                try
+                {
+                    //https://{apikey}:{password}@{hostname}/admin/api/{version}/{resource}.json
+                    var parsedUrl = new Uri(exampleUrl);
+                    var userInfo = parsedUrl.UserInfo.Split(":");
+                    vm.Shopify = new ShopifySettings()
+                    {
+                        ApiKey = userInfo[0],
+                        Password = userInfo[1],
+                        ShopName = parsedUrl.Host.Replace(".myshopify.com", "",
+                            StringComparison.InvariantCultureIgnoreCase)
+                    };
+                    command = "ShopifySaveCredentials";
+                }
+                catch (Exception)
+                {
+                    TempData[WellKnownTempData.ErrorMessage] = "The provided Example Url was invalid.";
+                    return View("Integrations", vm);
+                }
+            }
+
+            switch (command)
+            {
+                case "ShopifySaveCredentials":
+                {
+                    var shopify = vm.Shopify;
+                    var validCreds = shopify != null && shopify?.CredentialsPopulated() == true;
+                    if (!validCreds)
+                    {
+                        TempData[WellKnownTempData.ErrorMessage] = "Please provide valid Shopify credentials";
+                        return View("Integrations", vm);
+                    }
+
+                    var apiClient = new ShopifyApiClient(clientFactory, shopify.CreateShopifyApiCredentials());
+                    try
+                    {
+                        await apiClient.OrdersCount();
+                    }
+                    catch (ShopifyApiException)
+                    {
+                        TempData[WellKnownTempData.ErrorMessage] =
+                            "Shopify rejected provided credentials, please correct values and try again";
+                        return View("Integrations", vm);
+                    }
+
+                    var scopesGranted = await apiClient.CheckScopes();
+                    if (!scopesGranted.Contains("read_orders") || !scopesGranted.Contains("write_orders"))
+                    {
+                        TempData[WellKnownTempData.ErrorMessage] =
+                            "Please grant the private app permissions for read_orders, write_orders";
+                        return View("Integrations", vm);
+                    }
+
+                    // everything ready, proceed with saving Shopify integration credentials
+                    shopify.IntegratedAt = DateTimeOffset.Now;
+
+                    var blob = CurrentStore.GetStoreBlob();
+                    blob.Shopify = shopify;
+                    if (CurrentStore.SetStoreBlob(blob))
+                    {
+                        await _Repo.UpdateStore(CurrentStore);
+                    }
+
+                    TempData[WellKnownTempData.SuccessMessage] = "Shopify integration successfully updated";
+                    break;
+                }
+                case "ShopifyClearCredentials":
+                {
+                    var blob = CurrentStore.GetStoreBlob();
+                    blob.Shopify = null;
+                    if (CurrentStore.SetStoreBlob(blob))
+                    {
+                        await _Repo.UpdateStore(CurrentStore);
+                    }
+
+                    TempData[WellKnownTempData.SuccessMessage] = "Shopify integration credentials cleared";
+                    break;
+                }
+            }
+
+            return RedirectToAction(nameof(Integrations), new {storeId = CurrentStore.Id});
+        }
+    }
+}
diff --git a/BTCPayServer/Controllers/StoresController.cs b/BTCPayServer/Controllers/StoresController.cs
index dda4feff4..b828e9514 100644
--- a/BTCPayServer/Controllers/StoresController.cs
+++ b/BTCPayServer/Controllers/StoresController.cs
@@ -20,8 +20,10 @@ using BTCPayServer.Services;
 using BTCPayServer.Services.Apps;
 using BTCPayServer.Services.Invoices;
 using BTCPayServer.Services.Rates;
+using BTCPayServer.Services.Shopify;
 using BTCPayServer.Services.Stores;
 using BTCPayServer.Services.Wallets;
+using BundlerMinifier.TagHelpers;
 using Microsoft.AspNetCore.Authorization;
 using Microsoft.AspNetCore.Hosting;
 using Microsoft.AspNetCore.Identity;
@@ -54,15 +56,14 @@ namespace BTCPayServer.Controllers
             BTCPayNetworkProvider networkProvider,
             RateFetcher rateFactory,
             ExplorerClientProvider explorerProvider,
-            IFeeProviderFactory feeRateProvider,
             LanguageService langService,
-            IWebHostEnvironment env, IHttpClientFactory httpClientFactory,
             PaymentMethodHandlerDictionary paymentMethodHandlerDictionary,
             SettingsRepository settingsRepository,
             IAuthorizationService authorizationService,
             EventAggregator eventAggregator,
             CssThemeManager cssThemeManager,
-            AppService appService)
+            AppService appService,
+            IWebHostEnvironment webHostEnvironment)
         {
             _RateFactory = rateFactory;
             _Repo = repo;
@@ -71,17 +72,15 @@ namespace BTCPayServer.Controllers
             _LangService = langService;
             _TokenController = tokenController;
             _WalletProvider = walletProvider;
-            _Env = env;
-            _httpClientFactory = httpClientFactory;
             _paymentMethodHandlerDictionary = paymentMethodHandlerDictionary;
             _settingsRepository = settingsRepository;
             _authorizationService = authorizationService;
             _CssThemeManager = cssThemeManager;
             _appService = appService;
+            _webHostEnvironment = webHostEnvironment;
             _EventAggregator = eventAggregator;
             _NetworkProvider = networkProvider;
             _ExplorerProvider = explorerProvider;
-            _FeeRateProvider = feeRateProvider;
             _ServiceProvider = serviceProvider;
             _BtcpayServerOptions = btcpayServerOptions;
             _BTCPayEnv = btcpayEnv;
@@ -92,20 +91,18 @@ namespace BTCPayServer.Controllers
         readonly IServiceProvider _ServiceProvider;
         readonly BTCPayNetworkProvider _NetworkProvider;
         private readonly ExplorerClientProvider _ExplorerProvider;
-        private readonly IFeeProviderFactory _FeeRateProvider;
         readonly BTCPayWalletProvider _WalletProvider;
         readonly AccessTokenController _TokenController;
         readonly StoreRepository _Repo;
         readonly TokenRepository _TokenRepository;
         readonly UserManager<ApplicationUser> _UserManager;
         private readonly LanguageService _LangService;
-        readonly IWebHostEnvironment _Env;
-        private readonly IHttpClientFactory _httpClientFactory;
         private readonly PaymentMethodHandlerDictionary _paymentMethodHandlerDictionary;
         private readonly SettingsRepository _settingsRepository;
         private readonly IAuthorizationService _authorizationService;
         private readonly CssThemeManager _CssThemeManager;
         private readonly AppService _appService;
+        private readonly IWebHostEnvironment _webHostEnvironment;
         private readonly EventAggregator _EventAggregator;
 
         [TempData]
@@ -964,5 +961,8 @@ namespace BTCPayServer.Controllers
             });
 
         }
+
+
+
     }
 }
diff --git a/BTCPayServer/Data/StoreBlob.cs b/BTCPayServer/Data/StoreBlob.cs
index 7149a2c71..e0e8ffc1a 100644
--- a/BTCPayServer/Data/StoreBlob.cs
+++ b/BTCPayServer/Data/StoreBlob.cs
@@ -11,6 +11,7 @@ using BTCPayServer.Payments.CoinSwitch;
 using BTCPayServer.Rating;
 using BTCPayServer.Services.Mails;
 using BTCPayServer.Services.Rates;
+using BTCPayServer.Services.Shopify.Models;
 using Newtonsoft.Json;
 
 namespace BTCPayServer.Data
@@ -26,6 +27,8 @@ namespace BTCPayServer.Data
             RecommendedFeeBlockTarget = 1;
         }
 
+        public ShopifySettings Shopify { get; set; }
+
         [Obsolete("Use NetworkFeeMode instead")]
         [JsonProperty(DefaultValueHandling = DefaultValueHandling.Ignore)]
         public bool? NetworkFeeDisabled
diff --git a/BTCPayServer/HostedServices/InvoiceNotificationManager.cs b/BTCPayServer/HostedServices/InvoiceNotificationManager.cs
index 37d3048c1..eb8fefee4 100644
--- a/BTCPayServer/HostedServices/InvoiceNotificationManager.cs
+++ b/BTCPayServer/HostedServices/InvoiceNotificationManager.cs
@@ -331,17 +331,17 @@ namespace BTCPayServer.HostedServices
                        e.Name == InvoiceEvent.Completed ||
                        e.Name == InvoiceEvent.ExpiredPaidPartial
                      )
-                        Notify(invoice, e, false);
+                        _ = Notify(invoice, e, false);
                 }
 
                 if (e.Name == InvoiceEvent.Confirmed)
                 {
-                    Notify(invoice, e, false);
+                    _ = Notify(invoice, e, false);
                 }
 
                 if (invoice.ExtendedNotifications)
                 {
-                    Notify(invoice, e, true);
+                    _ = Notify(invoice, e, true);
                 }
             }));
 
diff --git a/BTCPayServer/Hosting/BTCPayServerServices.cs b/BTCPayServer/Hosting/BTCPayServerServices.cs
index ef5e32576..0dbb31fe0 100644
--- a/BTCPayServer/Hosting/BTCPayServerServices.cs
+++ b/BTCPayServer/Hosting/BTCPayServerServices.cs
@@ -25,6 +25,7 @@ using BTCPayServer.Services.Notifications;
 using BTCPayServer.Services.Notifications.Blobs;
 using BTCPayServer.Services.PaymentRequests;
 using BTCPayServer.Services.Rates;
+using BTCPayServer.Services.Shopify;
 using BTCPayServer.Services.Stores;
 using BTCPayServer.Services.Wallets;
 using BTCPayServer.U2F;
@@ -245,7 +246,8 @@ namespace BTCPayServer.Hosting
 
             services.AddSingleton<INotificationHandler, InvoiceEventNotification.Handler>();
             services.AddSingleton<INotificationHandler, PayoutNotification.Handler>();
-            
+
+            services.AddShopify();
 #if DEBUG
             services.AddSingleton<INotificationHandler, JunkNotification.Handler>();
 #endif    
@@ -295,12 +297,14 @@ namespace BTCPayServer.Hosting
                     rateLimits.SetZone($"zone={ZoneLimits.Login} rate=1000r/min burst=100 nodelay");
                     rateLimits.SetZone($"zone={ZoneLimits.Register} rate=1000r/min burst=100 nodelay");
                     rateLimits.SetZone($"zone={ZoneLimits.PayJoin} rate=1000r/min burst=100 nodelay");
+                    rateLimits.SetZone($"zone={ZoneLimits.Shopify} rate=1000r/min burst=100 nodelay");
                 }
                 else
                 {
                     rateLimits.SetZone($"zone={ZoneLimits.Login} rate=5r/min burst=3 nodelay");
                     rateLimits.SetZone($"zone={ZoneLimits.Register} rate=2r/min burst=2 nodelay");
                     rateLimits.SetZone($"zone={ZoneLimits.PayJoin} rate=5r/min burst=3 nodelay");
+                    rateLimits.SetZone($"zone={ZoneLimits.Shopify} rate=20r/min burst=3 nodelay");
                 }
                 return rateLimits;
             });
diff --git a/BTCPayServer/Models/StoreViewModels/IntegrationsViewModel.cs b/BTCPayServer/Models/StoreViewModels/IntegrationsViewModel.cs
new file mode 100644
index 000000000..d5b6d3b89
--- /dev/null
+++ b/BTCPayServer/Models/StoreViewModels/IntegrationsViewModel.cs
@@ -0,0 +1,15 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using BTCPayServer.Services.Shopify.Models;
+using static BTCPayServer.Data.StoreBlob;
+
+namespace BTCPayServer.Models.StoreViewModels
+{
+    public class IntegrationsViewModel
+    {
+        public ShopifySettings Shopify { get; set; }
+    }
+}
diff --git a/BTCPayServer/Services/Invoices/InvoiceEntity.cs b/BTCPayServer/Services/Invoices/InvoiceEntity.cs
index aff8665a4..cd80d7d31 100644
--- a/BTCPayServer/Services/Invoices/InvoiceEntity.cs
+++ b/BTCPayServer/Services/Invoices/InvoiceEntity.cs
@@ -259,11 +259,11 @@ namespace BTCPayServer.Services.Invoices
         [JsonProperty(DefaultValueHandling = DefaultValueHandling.Ignore)]
         public HashSet<string> InternalTags { get; set; } = new HashSet<string>();
 
-        public string[] GetInternalTags(string suffix)
+        public string[] GetInternalTags(string prefix)
         {
             return InternalTags == null ? Array.Empty<string>() : InternalTags
-                                                  .Where(t => t.StartsWith(suffix, StringComparison.InvariantCulture))
-                                                  .Select(t => t.Substring(suffix.Length)).ToArray();
+                                                  .Where(t => t.StartsWith(prefix, StringComparison.InvariantCulture))
+                                                  .Select(t => t.Substring(prefix.Length)).ToArray();
         }
 
         [Obsolete("Use GetDerivationStrategies instead")]
diff --git a/BTCPayServer/Services/Shopify/ApiModels/CreateScriptResponse.cs b/BTCPayServer/Services/Shopify/ApiModels/CreateScriptResponse.cs
new file mode 100644
index 000000000..d5560abd5
--- /dev/null
+++ b/BTCPayServer/Services/Shopify/ApiModels/CreateScriptResponse.cs
@@ -0,0 +1,31 @@
+using System;
+using Newtonsoft.Json;
+
+namespace BTCPayServer.Services.Shopify.ApiModels
+{
+    public class CreateScriptResponse
+    {
+        [JsonProperty("script_tag")]
+        public ScriptTag ScriptTag { get; set; }
+    }
+    
+    public class ScriptTag    {
+        [JsonProperty("id")]
+        public int Id { get; set; } 
+
+        [JsonProperty("src")]
+        public string Src { get; set; } 
+
+        [JsonProperty("event")]
+        public string Event { get; set; } 
+
+        [JsonProperty("created_at")]
+        public DateTime CreatedAt { get; set; } 
+
+        [JsonProperty("updated_at")]
+        public DateTime UpdatedAt { get; set; } 
+
+        [JsonProperty("display_scope")]
+        public string DisplayScope { get; set; } 
+    }
+}
diff --git a/BTCPayServer/Services/Shopify/ApiModels/CreateWebhookResponse.cs b/BTCPayServer/Services/Shopify/ApiModels/CreateWebhookResponse.cs
new file mode 100644
index 000000000..d4b7cc6e6
--- /dev/null
+++ b/BTCPayServer/Services/Shopify/ApiModels/CreateWebhookResponse.cs
@@ -0,0 +1,35 @@
+using System;
+using System.Collections.Generic;
+using Newtonsoft.Json;
+
+namespace BTCPayServer.Services.Shopify.ApiModels
+{
+    public class CreateWebhookResponse
+    {
+        [JsonProperty("webhook")] public Webhook Webhook { get; set; }
+    }
+
+    public class Webhook
+    {
+        [JsonProperty("id")] public int Id { get; set; }
+
+        [JsonProperty("address")] public string Address { get; set; }
+
+        [JsonProperty("topic")] public string Topic { get; set; }
+
+        [JsonProperty("created_at")] public DateTime CreatedAt { get; set; }
+
+        [JsonProperty("updated_at")] public DateTime UpdatedAt { get; set; }
+
+        [JsonProperty("format")] public string Format { get; set; }
+
+        [JsonProperty("fields")] public List<object> Fields { get; set; }
+
+        [JsonProperty("metafield_namespaces")] public List<object> MetafieldNamespaces { get; set; }
+
+        [JsonProperty("api_version")] public string ApiVersion { get; set; }
+
+        [JsonProperty("private_metafield_namespaces")]
+        public List<object> PrivateMetafieldNamespaces { get; set; }
+    }
+}
diff --git a/BTCPayServer/Services/Shopify/ApiModels/DataHolders/TransactionDataHolder.cs b/BTCPayServer/Services/Shopify/ApiModels/DataHolders/TransactionDataHolder.cs
new file mode 100644
index 000000000..136b4949d
--- /dev/null
+++ b/BTCPayServer/Services/Shopify/ApiModels/DataHolders/TransactionDataHolder.cs
@@ -0,0 +1,33 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace BTCPayServer.Services.Shopify.ApiModels.DataHolders
+{
+    public class TransactionDataHolder
+    {
+        public long id { get; set; }
+        public long? order_id { get; set; }
+        public string kind { get; set; }
+        public string gateway { get; set; }
+        public string status { get; set; }
+        public string message { get; set; }
+        public DateTimeOffset created_at { get; set; }
+        public bool test { get; set; }
+        public string authorization { get; set; }
+        public string location_id { get; set; }
+        public string user_id { get; set; }
+        public long? parent_id { get; set; }
+        public DateTimeOffset processed_at { get; set; }
+        public string device_id { get; set; }
+        public object receipt { get; set; }
+        public string error_code { get; set; }
+        public string source_name { get; set; }
+        public string currency_exchange_adjustment { get; set; }
+        public string amount { get; set; }
+        public string currency { get; set; }
+        public string admin_graphql_api_id { get; set; }
+    }
+}
diff --git a/BTCPayServer/Services/Shopify/ApiModels/OrdersCountResp.cs b/BTCPayServer/Services/Shopify/ApiModels/OrdersCountResp.cs
new file mode 100644
index 000000000..7aef830b9
--- /dev/null
+++ b/BTCPayServer/Services/Shopify/ApiModels/OrdersCountResp.cs
@@ -0,0 +1,10 @@
+using Newtonsoft.Json;
+
+namespace BTCPayServer.Services.Shopify.ApiModels
+{
+    public class CountResponse
+    {
+        [JsonProperty("count")] 
+        public long Count { get; set; }
+    }
+}
diff --git a/BTCPayServer/Services/Shopify/ApiModels/ShopifyOrder.cs b/BTCPayServer/Services/Shopify/ApiModels/ShopifyOrder.cs
new file mode 100644
index 000000000..1b7e513fe
--- /dev/null
+++ b/BTCPayServer/Services/Shopify/ApiModels/ShopifyOrder.cs
@@ -0,0 +1,19 @@
+using System.Collections.Generic;
+using Newtonsoft.Json;
+
+namespace BTCPayServer.Services.Shopify.ApiModels
+{
+    public class ShopifyOrder
+    {
+        [JsonProperty("id")]
+        public string Id { get; set; }
+        [JsonProperty("total_price")]
+        public decimal TotalPrice { get; set; }
+        [JsonProperty("currency")]
+        public string Currency { get; set; }
+        [JsonProperty("financial_status")]
+        public string FinancialStatus { get; set; }
+        [JsonProperty("transactions")]
+        public IEnumerable<ShopifyTransaction> Transactions { get; set; }
+    }
+}
diff --git a/BTCPayServer/Services/Shopify/ApiModels/ShopifyTransaction.cs b/BTCPayServer/Services/Shopify/ApiModels/ShopifyTransaction.cs
new file mode 100644
index 000000000..80ed1842c
--- /dev/null
+++ b/BTCPayServer/Services/Shopify/ApiModels/ShopifyTransaction.cs
@@ -0,0 +1,48 @@
+using System;
+using Newtonsoft.Json;
+
+namespace BTCPayServer.Services.Shopify.ApiModels
+{
+    public class ShopifyTransaction
+    {
+        [JsonProperty("amount")]
+        public decimal? Amount { get; set; }
+
+        [JsonProperty("authorization")]
+        public string Authorization { get; set; }
+
+        [JsonProperty("created_at")]
+        public DateTimeOffset? CreatedAt { get; set; }
+
+        [JsonProperty("device_id")]
+        public string DeviceId { get; set; }
+
+        [JsonProperty("gateway")]
+        public string Gateway { get; set; }
+        [JsonProperty("kind")]
+        public string Kind { get; set; }
+        [JsonProperty("order_id")]
+        public long? OrderId { get; set; }
+
+        /// <summary>
+        /// A standardized error code, e.g. 'incorrect_number', independent of the payment provider. Value can be null. A full list of known values can be found at https://help.shopify.com/api/reference/transaction.
+        /// </summary>
+        [JsonProperty("error_code")]
+        public string ErrorCode { get; set; }
+
+        /// <summary>
+        /// The status of the transaction. Valid values are: pending, failure, success or error.
+        /// </summary>
+        [JsonProperty("status")]
+        public string Status { get; set; }
+        [JsonProperty("test")]
+        public bool? Test { get; set; }
+        [JsonProperty("currency")]
+        public string Currency { get; set; }
+        /// <summary>
+        /// This property is undocumented by Shopify.
+        /// </summary>
+        [JsonProperty("parent_id")]
+        public long? ParentId { get; set; }
+    }
+}
diff --git a/BTCPayServer/Services/Shopify/ApiModels/TransactionsCreateReq.cs b/BTCPayServer/Services/Shopify/ApiModels/TransactionsCreateReq.cs
new file mode 100644
index 000000000..90df0d1e5
--- /dev/null
+++ b/BTCPayServer/Services/Shopify/ApiModels/TransactionsCreateReq.cs
@@ -0,0 +1,19 @@
+namespace BTCPayServer.Services.Shopify.ApiModels
+{
+    public class TransactionsCreateReq
+    {
+        public DataHolder transaction { get; set; }
+
+        public class DataHolder
+        {
+            public string currency { get; set; }
+            public string amount { get; set; }
+            public string kind { get; set; }
+            public long? parent_id { get; set; }
+            public string gateway { get; set; }
+            public string source { get; set; }
+            public string status { get; set; }
+            public string authorization { get; set; }
+        }
+    }
+}
diff --git a/BTCPayServer/Services/Shopify/ApiModels/TransactionsCreateResp.cs b/BTCPayServer/Services/Shopify/ApiModels/TransactionsCreateResp.cs
new file mode 100644
index 000000000..ae38f3f60
--- /dev/null
+++ b/BTCPayServer/Services/Shopify/ApiModels/TransactionsCreateResp.cs
@@ -0,0 +1,14 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using BTCPayServer.Services.Shopify.ApiModels.DataHolders;
+
+namespace BTCPayServer.Services.Shopify.ApiModels
+{
+    public class TransactionsCreateResp
+    {
+        public TransactionDataHolder transaction { get; set; }
+    }
+}
diff --git a/BTCPayServer/Services/Shopify/ApiModels/TransactionsListResp.cs b/BTCPayServer/Services/Shopify/ApiModels/TransactionsListResp.cs
new file mode 100644
index 000000000..595d84f5f
--- /dev/null
+++ b/BTCPayServer/Services/Shopify/ApiModels/TransactionsListResp.cs
@@ -0,0 +1,10 @@
+using System.Collections.Generic;
+using BTCPayServer.Services.Shopify.ApiModels.DataHolders;
+
+namespace BTCPayServer.Services.Shopify.ApiModels
+{
+    public class TransactionsListResp
+    {
+        public List<TransactionDataHolder> transactions { get; set; }
+    }
+}
diff --git a/BTCPayServer/Services/Shopify/Models/ShopifySettings.cs b/BTCPayServer/Services/Shopify/Models/ShopifySettings.cs
new file mode 100644
index 000000000..f138a26f1
--- /dev/null
+++ b/BTCPayServer/Services/Shopify/Models/ShopifySettings.cs
@@ -0,0 +1,22 @@
+using System;
+using System.ComponentModel.DataAnnotations;
+
+namespace BTCPayServer.Services.Shopify.Models
+{
+    public class ShopifySettings
+    {
+        [Display(Name = "Shop Name")]
+        public string ShopName { get; set; }
+        public string ApiKey { get; set; }
+        public string Password { get; set; }
+
+        public bool CredentialsPopulated()
+        {
+            return
+                !string.IsNullOrWhiteSpace(ShopName) &&
+                !string.IsNullOrWhiteSpace(ApiKey) &&
+                !string.IsNullOrWhiteSpace(Password);
+        }
+        public DateTimeOffset? IntegratedAt { get; set; }
+    }
+}
diff --git a/BTCPayServer/Services/Shopify/OrderTransactionRegisterLogic.cs b/BTCPayServer/Services/Shopify/OrderTransactionRegisterLogic.cs
new file mode 100644
index 000000000..1465bf071
--- /dev/null
+++ b/BTCPayServer/Services/Shopify/OrderTransactionRegisterLogic.cs
@@ -0,0 +1,88 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+using BTCPayServer.Services.Shopify.ApiModels;
+using BTCPayServer.Services.Shopify.ApiModels.DataHolders;
+
+namespace BTCPayServer.Services.Shopify
+{
+    public class OrderTransactionRegisterLogic
+    {
+        private readonly ShopifyApiClient _client;
+
+        public OrderTransactionRegisterLogic(ShopifyApiClient client)
+        {
+            _client = client;
+        }
+
+        private static string[] _keywords = new[] { "bitcoin", "btc", "btcpayserver", "btcpay server" };
+        public async Task<TransactionsCreateResp> Process(string orderId, string invoiceId, string currency, string amountCaptured, bool success)
+        {
+            currency = currency.ToUpperInvariant().Trim();
+            var existingShopifyOrderTransactions = (await _client.TransactionsList(orderId)).transactions;
+            var baseParentTransaction = existingShopifyOrderTransactions.FirstOrDefault();
+            if (baseParentTransaction is null ||
+                !_keywords.Any(a => baseParentTransaction.gateway.Contains(a, StringComparison.InvariantCultureIgnoreCase)))
+            {
+                return null;
+            }
+
+            //technically, this exploit should not be possible as we use internal invoice tags to verify that the invoice was created by our controlled, dedicated endpoint.
+            if (currency.ToUpperInvariant().Trim() != baseParentTransaction.currency.ToUpperInvariant().Trim())
+            {
+                // because of parent_id present, currency will always be the one from parent transaction
+                // malicious attacker could potentially exploit this by creating invoice 
+                // in different currency and paying that one, registering order on Shopify as paid
+                // so if currency is supplied and is different from parent transaction currency we just won't register
+                return null;
+            }
+
+            var kind = "capture";
+            var parentId = baseParentTransaction.id;
+            var status = success ? "success" : "failure";
+            //find all existing transactions recorded around this invoice id 
+            var existingShopifyOrderTransactionsOnSameInvoice =
+                existingShopifyOrderTransactions.Where(holder => holder.authorization == invoiceId);
+
+            //filter out the successful ones
+            var successfulActions =
+                existingShopifyOrderTransactionsOnSameInvoice.Where(holder => holder.status == "success").ToArray();
+
+            //of the successful ones, get the ones we registered as a valid payment
+            var successfulCaptures = successfulActions.Where(holder => holder.kind == "capture").ToArray();
+
+            //of the successful ones, get the ones we registered as a voiding of a previous successful payment
+            var refunds = successfulActions.Where(holder => holder.kind == "refund").ToArray();
+
+            //if we are working with a non-success registration, but see that we have previously registered this invoice as a success, we switch to creating a "void" transaction, which in shopify terms is a refund.
+            if (!success && successfulCaptures.Length > 0 && (successfulCaptures.Length - refunds.Length) > 0)
+            {
+                kind = "void";
+                parentId = successfulCaptures.Last().id;
+                status = "success";
+            }
+            //if we are working with a success registration, but can see that we have already had a successful transaction saved, get outta here
+            else if (success && successfulCaptures.Length > 0 && (successfulCaptures.Length - refunds.Length) > 0)
+            {
+                return null;
+            }
+            var createTransaction = new TransactionsCreateReq
+            {
+                transaction = new TransactionsCreateReq.DataHolder
+                {
+                    parent_id = parentId,
+                    currency = currency,
+                    amount = amountCaptured,
+                    kind = kind,
+                    gateway = "BTCPayServer",
+                    source = "external",
+                    authorization = invoiceId,
+                    status = status
+                }
+            };
+            var createResp = await _client.TransactionCreate(orderId, createTransaction);
+            return createResp;
+        }
+    }
+}
diff --git a/BTCPayServer/Services/Shopify/ShopifyApiClient.cs b/BTCPayServer/Services/Shopify/ShopifyApiClient.cs
new file mode 100644
index 000000000..4d1accd7d
--- /dev/null
+++ b/BTCPayServer/Services/Shopify/ShopifyApiClient.cs
@@ -0,0 +1,138 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Net.Http;
+using System.Text;
+using System.Threading.Tasks;
+using BTCPayServer.Services.Shopify.ApiModels;
+using DBriize.Utils;
+using Newtonsoft.Json;
+using Newtonsoft.Json.Linq;
+
+namespace BTCPayServer.Services.Shopify
+{
+    public class ShopifyApiClient
+    {
+        private readonly HttpClient _httpClient;
+        private readonly ShopifyApiClientCredentials _credentials;
+
+        public ShopifyApiClient(IHttpClientFactory httpClientFactory, ShopifyApiClientCredentials credentials)
+        {
+            if (httpClientFactory != null)
+            {
+                _httpClient = httpClientFactory.CreateClient(nameof(ShopifyApiClient));
+            }
+            else // tests don't provide IHttpClientFactory
+            {
+                _httpClient = new HttpClient();
+            }
+
+            _credentials = credentials;
+
+            var bearer = $"{_credentials.ApiKey}:{_credentials.ApiPassword}";
+            bearer = Encoding.UTF8.GetBytes(bearer).ToBase64String();
+
+            _httpClient.DefaultRequestHeaders.Add("Authorization", "Basic " + bearer);
+        }
+
+        private HttpRequestMessage CreateRequest(string shopName, HttpMethod method, string action,
+            string relativeUrl = null)
+        {
+            var url =
+                $"https://{(shopName.Contains(".", StringComparison.InvariantCulture) ? shopName : $"{shopName}.myshopify.com")}/{relativeUrl ?? ("admin/api/2020-07/" + action)}";
+            var req = new HttpRequestMessage(method, url);
+            return req;
+        }
+
+        private async Task<string> SendRequest(HttpRequestMessage req)
+        {
+            using var resp = await _httpClient.SendAsync(req);
+
+            var strResp = await resp.Content.ReadAsStringAsync();
+            if (strResp?.StartsWith("{\"errors\":\"[API] Invalid API key or access token", StringComparison.OrdinalIgnoreCase) == true)
+                throw new ShopifyApiException("Invalid API key or access token");
+
+            return strResp;
+        }
+
+        public async Task<CreateWebhookResponse> CreateWebhook(string topic, string address, string format = "json")
+        {
+            var req = CreateRequest(_credentials.ShopName, HttpMethod.Post, $"webhooks.json");
+            req.Content = new StringContent(JsonConvert.SerializeObject(new {topic, address, format}), Encoding.UTF8,
+                "application/json");
+            var strResp = await SendRequest(req);
+
+            return JsonConvert.DeserializeObject<CreateWebhookResponse>(strResp);
+        }
+
+        public async Task RemoveWebhook(string id)
+        {
+            var req = CreateRequest(_credentials.ShopName, HttpMethod.Delete, $"webhooks/{id}.json");
+            var strResp = await SendRequest(req);
+        }
+
+        public async Task<string[]> CheckScopes()
+        {
+            var req = CreateRequest(_credentials.ShopName, HttpMethod.Get, null, "admin/oauth/access_scopes.json");
+            return JObject.Parse(await SendRequest(req))["access_scopes"].Values<JToken>()
+                .Select(token => token["handle"].Value<string>()).ToArray();
+        }
+
+        public async Task<TransactionsListResp> TransactionsList(string orderId)
+        {
+            var req = CreateRequest(_credentials.ShopName, HttpMethod.Get, $"orders/{orderId}/transactions.json");
+
+            var strResp = await SendRequest(req);
+
+            var parsed = JsonConvert.DeserializeObject<TransactionsListResp>(strResp);
+
+            return parsed;
+        }
+
+        public async Task<TransactionsCreateResp> TransactionCreate(string orderId, TransactionsCreateReq txnCreate)
+        {
+            var postJson = JsonConvert.SerializeObject(txnCreate);
+
+            var req = CreateRequest(_credentials.ShopName, HttpMethod.Post, $"orders/{orderId}/transactions.json");
+            req.Content = new StringContent(postJson, Encoding.UTF8, "application/json");
+
+            var strResp = await SendRequest(req);
+            return JsonConvert.DeserializeObject<TransactionsCreateResp>(strResp);
+        }
+
+        public async Task<ShopifyOrder> GetOrder(string orderId)
+        {
+            var req = CreateRequest(_credentials.ShopName, HttpMethod.Get,
+                $"orders/{orderId}.json?fields=id,total_price,currency,transactions,financial_status");
+
+            var strResp = await SendRequest(req);
+
+            return JObject.Parse(strResp)["order"].ToObject<ShopifyOrder>();
+        }
+
+        public async Task<long> OrdersCount()
+        {
+            var req = CreateRequest(_credentials.ShopName, HttpMethod.Get, $"orders/count.json");
+            var strResp = await SendRequest(req);
+
+            var parsed = JsonConvert.DeserializeObject<CountResponse>(strResp);
+
+            return parsed.Count;
+        }
+
+        public async Task<bool> OrderExists(string orderId)
+        {
+            var req = CreateRequest(_credentials.ShopName, HttpMethod.Get, $"orders/{orderId}.json?fields=id");
+            var strResp = await SendRequest(req);
+
+            return strResp?.Contains(orderId, StringComparison.OrdinalIgnoreCase) == true;
+        }
+    }
+}
+
+public class ShopifyApiClientCredentials
+{
+    public string ShopName { get; set; }
+    public string ApiKey { get; set; }
+    public string ApiPassword { get; set; }
+}
diff --git a/BTCPayServer/Services/Shopify/ShopifyApiException.cs b/BTCPayServer/Services/Shopify/ShopifyApiException.cs
new file mode 100644
index 000000000..28ca4c3ee
--- /dev/null
+++ b/BTCPayServer/Services/Shopify/ShopifyApiException.cs
@@ -0,0 +1,15 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace BTCPayServer.Services.Shopify
+{
+    public class ShopifyApiException : Exception
+    {
+        public ShopifyApiException(string message) : base(message)
+        {
+        }
+    }
+}
diff --git a/BTCPayServer/Services/Shopify/ShopifyExtensions.cs b/BTCPayServer/Services/Shopify/ShopifyExtensions.cs
new file mode 100644
index 000000000..a92aa524c
--- /dev/null
+++ b/BTCPayServer/Services/Shopify/ShopifyExtensions.cs
@@ -0,0 +1,24 @@
+using BTCPayServer.Services.Shopify.Models;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Hosting;
+
+namespace BTCPayServer.Services.Shopify
+{
+    public static class ShopifyExtensions
+    {
+        public static ShopifyApiClientCredentials CreateShopifyApiCredentials(this ShopifySettings shopify)
+        {
+            return new ShopifyApiClientCredentials
+            {
+                ShopName = shopify.ShopName,
+                ApiKey = shopify.ApiKey,
+                ApiPassword = shopify.Password
+            };
+        }
+
+        public static void AddShopify(this IServiceCollection services)
+        {
+            services.AddSingleton<IHostedService, ShopifyOrderMarkerHostedService>();
+        }
+    }
+}
diff --git a/BTCPayServer/Services/Shopify/ShopifyOrderMarkerHostedService.cs b/BTCPayServer/Services/Shopify/ShopifyOrderMarkerHostedService.cs
new file mode 100644
index 000000000..4f2ccca2c
--- /dev/null
+++ b/BTCPayServer/Services/Shopify/ShopifyOrderMarkerHostedService.cs
@@ -0,0 +1,114 @@
+using System;
+using System.Globalization;
+using System.Linq;
+using System.Net.Http;
+using System.Threading;
+using System.Threading.Tasks;
+using BTCPayServer.Client.Models;
+using BTCPayServer.Data;
+using BTCPayServer.Events;
+using BTCPayServer.HostedServices;
+using BTCPayServer.Logging;
+using BTCPayServer.Services.Invoices;
+using BTCPayServer.Services.Shopify.Models;
+using BTCPayServer.Services.Stores;
+using Microsoft.Extensions.Logging;
+
+namespace BTCPayServer.Services.Shopify
+{
+    public class ShopifyOrderMarkerHostedService : EventHostedServiceBase
+    {
+        private readonly StoreRepository _storeRepository;
+        private readonly IHttpClientFactory _httpClientFactory;
+
+        public ShopifyOrderMarkerHostedService(EventAggregator eventAggregator,
+            StoreRepository storeRepository,
+            IHttpClientFactory httpClientFactory) : base(eventAggregator)
+        {
+            _storeRepository = storeRepository;
+            _httpClientFactory = httpClientFactory;
+        }
+
+        public const string SHOPIFY_ORDER_ID_PREFIX = "shopify-";
+
+        protected override void SubscribeToEvents()
+        {
+            Subscribe<InvoiceEvent>();
+            base.SubscribeToEvents();
+        }
+
+        protected override async Task ProcessEvent(object evt, CancellationToken cancellationToken)
+        {
+            if (evt is InvoiceEvent invoiceEvent && !new[]
+            {
+                InvoiceEvent.Created, InvoiceEvent.Confirmed, InvoiceEvent.ExpiredPaidPartial,
+                InvoiceEvent.ReceivedPayment, InvoiceEvent.PaidInFull
+            }.Contains(invoiceEvent.Name))
+            {
+                var invoice = invoiceEvent.Invoice;
+                var shopifyOrderId = invoice.GetInternalTags(SHOPIFY_ORDER_ID_PREFIX).FirstOrDefault();
+                if (shopifyOrderId != null)
+                {
+                    if (new[] {InvoiceStatus.Invalid, InvoiceStatus.Expired}.Contains(invoice.GetInvoiceState()
+                        .Status) && invoice.ExceptionStatus != InvoiceExceptionStatus.None)
+                    {
+                        //you have failed us, customer
+
+                        await RegisterTransaction(invoice, shopifyOrderId, false);
+                    }
+                    else if (new[] {InvoiceStatus.Complete, InvoiceStatus.Confirmed}.Contains(
+                        invoice.Status))
+                    {
+                        await RegisterTransaction(invoice, shopifyOrderId, true);
+                    }
+                }
+            }
+
+            await base.ProcessEvent(evt, cancellationToken);
+        }
+
+        private async Task RegisterTransaction(InvoiceEntity invoice, string shopifyOrderId, bool success)
+        {
+            var storeData = await _storeRepository.FindStore(invoice.StoreId);
+            var storeBlob = storeData.GetStoreBlob();
+
+            // ensure that store in question has shopify integration turned on 
+            // and that invoice's orderId has shopify specific prefix
+            if (storeBlob.Shopify?.IntegratedAt.HasValue == true)
+            {
+                var client = CreateShopifyApiClient(storeBlob.Shopify);
+                if (!await client.OrderExists(shopifyOrderId))
+                {
+                    // don't register transactions for orders that don't exist on shopify
+                    return;
+                }
+
+                // if we got this far, we likely need to register this invoice's payment on Shopify
+                // OrderTransactionRegisterLogic has check if transaction is already registered which is why we're passing invoice.Id
+                try
+                {
+                    var logic = new OrderTransactionRegisterLogic(client);
+                    var resp = await logic.Process(shopifyOrderId, invoice.Id, invoice.Currency,
+                        invoice.Price.ToString(CultureInfo.InvariantCulture), success);
+                    if (resp != null)
+                    {
+                        Logs.PayServer.LogInformation($"Registered order transaction {invoice.Price}{invoice.Currency} on Shopify. " +
+                                                      $"Triggered by invoiceId: {invoice.Id}, Shopify orderId: {shopifyOrderId}, Success: {success}");
+                    }
+                }
+                catch (Exception ex)
+                {
+                    Logs.PayServer.LogError(ex,
+                        $"Shopify error while trying to register order transaction. " +
+                        $"Triggered by invoiceId: {invoice.Id}, Shopify orderId: {shopifyOrderId}");
+                }
+            }
+        }
+
+
+        private ShopifyApiClient CreateShopifyApiClient(ShopifySettings shopify)
+        {
+            return new ShopifyApiClient(_httpClientFactory, shopify.CreateShopifyApiCredentials());
+        }
+    }
+}
diff --git a/BTCPayServer/Views/Stores/Integrations.cshtml b/BTCPayServer/Views/Stores/Integrations.cshtml
new file mode 100644
index 000000000..769fbc365
--- /dev/null
+++ b/BTCPayServer/Views/Stores/Integrations.cshtml
@@ -0,0 +1,39 @@
+@model IntegrationsViewModel
+@{
+    Layout = "../Shared/_NavLayout.cshtml";
+    ViewData.SetActivePageAndTitle(StoreNavPages.Integrations, "Integrations");
+}
+
+<partial name="_StatusMessage" />
+
+@if (!ViewContext.ModelState.IsValid)
+{
+    <div class="row">
+        <div class="col-md-6">
+            <div asp-validation-summary="All" class="text-danger"></div>
+        </div>
+    </div>
+}
+
+<div class="row">
+    <div class="col-md-8">
+       <partial name="Integrations/Shopify"/>
+
+        <h4 class="mb-3 mt-5">
+            Other Integrations
+        </h4>
+        <p>
+            Take a look at documentation for the list of other integrations we support and the directions on how to enable them:
+            <ul>
+                <li><a href="https://docs.btcpayserver.org/WooCommerce/" target="_blank">WooCommerce</a></li>
+                <li><a href="https://docs.btcpayserver.org/Drupal/" target="_blank">Drupal</a></li>
+                <li><a href="https://docs.btcpayserver.org/Magento/" target="_blank">Magento</a></li>
+                <li><a href="https://docs.btcpayserver.org/PrestaShop/" target="_blank">PrestaShop</a></li>
+            </ul>
+        </p>
+    </div>
+</div>
+
+@section Scripts {
+    @await Html.PartialAsync("_ValidationScriptsPartial")
+}
diff --git a/BTCPayServer/Views/Stores/Integrations/Shopify.cshtml b/BTCPayServer/Views/Stores/Integrations/Shopify.cshtml
new file mode 100644
index 000000000..a45b4047a
--- /dev/null
+++ b/BTCPayServer/Views/Stores/Integrations/Shopify.cshtml
@@ -0,0 +1,81 @@
+@model IntegrationsViewModel
+@{
+    var shopify = Model.Shopify;
+    var shopifyCredsSet = shopify?.IntegratedAt.HasValue is true;
+    var shopifyUrl = shopify is null? null:  !shopify?.ShopName?.Contains(".") is true ? $"https://{shopify.ShopName}.myshopify.com" : shopify.ShopName;
+}
+<form method="post" id="shopifyForm">
+    <h4 class="mb-3">
+        Shopify
+        <a href="https://docs.btcpayserver.org/Shopify" target="_blank">
+            <span class="fa fa-question-circle-o" title="More information..."></span>
+        </a>
+    </h4>
+    @if (!shopifyCredsSet)
+    {
+        <p class="alert alert-info">Create a Shopify Private App with the permissions "Orders - Read and write"</p>
+
+        <div class="form-group">
+            <label for="exampleUrl">Example Url from Shopify Private App</label>
+            <input class="form-control" id="exampleUrl" name="exampleUrl">
+        </div>
+
+        <button name="command" type="submit" class="btn btn-primary" value="ShopifySaveCredentials">Connect to Shopify</button>
+    }
+    else
+    {
+        <div class="form-group">
+            <label asp-for="Shopify.ShopName"></label>
+            <div class="input-group">
+                @if (!Model.Shopify?.ShopName?.Contains(".") is true)
+                {
+                    <div class="input-group-prepend">
+                        <span class="input-group-text">https://</span>
+                    </div>
+                }
+                <input asp-for="Shopify.ShopName" class="form-control" readonly="@shopifyCredsSet" />
+
+                @if (!Model.Shopify?.ShopName?.Contains(".") is true)
+                {
+                    <div class="input-group-append">
+                        <span class="input-group-text">.myshopify.com</span>
+                    </div>
+                }
+            </div>
+            <span asp-validation-for="Shopify.ShopName" class="text-danger"></span>
+        </div>
+
+        <div class="form-group">
+            <label asp-for="Shopify.ApiKey"></label>
+            <input asp-for="Shopify.ApiKey" class="form-control" readonly="@shopifyCredsSet" />
+            <span asp-validation-for="Shopify.ApiKey" class="text-danger"></span>
+        </div>
+
+        <div class="form-group">
+            <label asp-for="Shopify.Password"></label>
+            <input asp-for="Shopify.Password" class="form-control" type="password" value="@Model.Shopify?.Password" readonly="@shopifyCredsSet" />
+            <span asp-validation-for="Shopify.Password" class="text-danger"></span>
+        </div>
+        <div class="alert alert-warning">
+            <p>
+                In Shopify please paste following script at <a href="@shopifyUrl/admin/settings/checkout#PolarisTextField1" target="_blank" class="font-weight-bold"> Settings &gt; Checkout &gt; Order Processing &gt; Additional Scripts</a>
+            </p>
+            <kbd style="display: block; word-break: break-all;">
+                @($"<script src='{Url.Action("ShopifyJavascript", "Stores", new {storeId = Context.GetRouteValue("storeId")}, Context.Request.Scheme)}'></script>")
+            </kbd>
+        </div>
+        <p class="alert alert-warning">
+            In Shopify please add a payment method at <a target="_blank" href="@shopifyUrl/admin/settings/payments" class="font-weight-bold"> Settings &gt; Payments &gt; Manual Payment Methods</a> with the name <kbd>Bitcoin with BTCPay Server</kbd>
+        </p>
+
+        <p class="alert alert-success">
+            Orders on <b>@shopify.ShopName</b>.myshopify.com will be marked as paid on successful invoice payment.
+            Started: @shopify.IntegratedAt.Value.ToBrowserDate()
+        </p>
+
+        <button name="command" type="submit" class="btn btn-danger" value="ShopifyClearCredentials">
+            Stop Shopify calls and clear credentials
+        </button>
+    }
+
+</form>
diff --git a/BTCPayServer/Views/Stores/StoreNavPages.cs b/BTCPayServer/Views/Stores/StoreNavPages.cs
index ab8060240..13f1873f8 100644
--- a/BTCPayServer/Views/Stores/StoreNavPages.cs
+++ b/BTCPayServer/Views/Stores/StoreNavPages.cs
@@ -2,6 +2,6 @@ namespace BTCPayServer.Views.Stores
 {
     public enum StoreNavPages
     {
-        ActivePage, Index, Rates, Checkout, Tokens, Users, PayButton
+        ActivePage, Index, Rates, Checkout, Tokens, Users, PayButton, Integrations
     }
 }
diff --git a/BTCPayServer/Views/Stores/_Nav.cshtml b/BTCPayServer/Views/Stores/_Nav.cshtml
index 2a3fd3755..47d4c3090 100644
--- a/BTCPayServer/Views/Stores/_Nav.cshtml
+++ b/BTCPayServer/Views/Stores/_Nav.cshtml
@@ -1,14 +1,15 @@
 <div class="nav flex-column nav-pills mb-4">
-    <a id="@(nameof(StoreNavPages.Index))"class="nav-link @ViewData.IsActivePage(StoreNavPages.Index)" asp-controller="Stores" asp-action="UpdateStore" asp-route-storeId="@this.Context.GetRouteValue("storeId")">General settings</a>
-    <a id="@(nameof(StoreNavPages.Rates))"class="nav-link @ViewData.IsActivePage(StoreNavPages.Rates)" asp-controller="Stores" asp-action="Rates" asp-route-storeId="@this.Context.GetRouteValue("storeId")">Rates</a>
-    <a id="@(nameof(StoreNavPages.Checkout))"class="nav-link @ViewData.IsActivePage(StoreNavPages.Checkout)" asp-controller="Stores" asp-action="CheckoutExperience" asp-route-storeId="@this.Context.GetRouteValue("storeId")">Checkout experience</a>
-    <a id="@(nameof(StoreNavPages.Tokens))"class="nav-link @ViewData.IsActivePage(StoreNavPages.Tokens)" asp-controller="Stores" asp-action="ListTokens" asp-route-storeId="@this.Context.GetRouteValue("storeId")">Access Tokens</a>
-    <a id="@(nameof(StoreNavPages.Users))"class="nav-link @ViewData.IsActivePage(StoreNavPages.Users)" asp-controller="Stores" asp-action="StoreUsers" asp-route-storeId="@this.Context.GetRouteValue("storeId")">Users</a>
-    <a id="@(nameof(StoreNavPages.PayButton))"class="nav-link @ViewData.IsActivePage(StoreNavPages.PayButton)" asp-controller="Stores" asp-action="PayButton" asp-route-storeId="@this.Context.GetRouteValue("storeId")">Pay Button</a>
+    <a id="@(nameof(StoreNavPages.Index))" class="nav-link @ViewData.IsActivePage(StoreNavPages.Index)" asp-controller="Stores" asp-action="UpdateStore" asp-route-storeId="@this.Context.GetRouteValue("storeId")">General settings</a>
+    <a id="@(nameof(StoreNavPages.Rates))" class="nav-link @ViewData.IsActivePage(StoreNavPages.Rates)" asp-controller="Stores" asp-action="Rates" asp-route-storeId="@this.Context.GetRouteValue("storeId")">Rates</a>
+    <a id="@(nameof(StoreNavPages.Checkout))" class="nav-link @ViewData.IsActivePage(StoreNavPages.Checkout)" asp-controller="Stores" asp-action="CheckoutExperience" asp-route-storeId="@this.Context.GetRouteValue("storeId")">Checkout experience</a>
+    <a id="@(nameof(StoreNavPages.Tokens))" class="nav-link @ViewData.IsActivePage(StoreNavPages.Tokens)" asp-controller="Stores" asp-action="ListTokens" asp-route-storeId="@this.Context.GetRouteValue("storeId")">Access Tokens</a>
+    <a id="@(nameof(StoreNavPages.Users))" class="nav-link @ViewData.IsActivePage(StoreNavPages.Users)" asp-controller="Stores" asp-action="StoreUsers" asp-route-storeId="@this.Context.GetRouteValue("storeId")">Users</a>
+    <a id="@(nameof(StoreNavPages.PayButton))" class="nav-link @ViewData.IsActivePage(StoreNavPages.PayButton)" asp-controller="Stores" asp-action="PayButton" asp-route-storeId="@this.Context.GetRouteValue("storeId")">Pay Button</a>
+    <a id="@(nameof(StoreNavPages.Integrations))" class="nav-link @ViewData.IsActivePage(StoreNavPages.Integrations)" asp-controller="Stores" asp-action="Integrations" asp-route-storeId="@this.Context.GetRouteValue("storeId")">Integrations</a>
     @inject IEnumerable<BTCPayServer.Contracts.IStoreNavExtension> Extensions;
     @foreach (var extension in Extensions)
     {
-        <partial name="@extension.Partial"/>
+        <partial name="@extension.Partial" />
     }
 </div>
 
diff --git a/BTCPayServer/ZoneLimits.cs b/BTCPayServer/ZoneLimits.cs
index 69edb48aa..dc8feb637 100644
--- a/BTCPayServer/ZoneLimits.cs
+++ b/BTCPayServer/ZoneLimits.cs
@@ -5,5 +5,6 @@ namespace BTCPayServer
         public const string Login = "btcpaylogin";
         public const string Register = "btcpayregister";
         public const string PayJoin = "PayJoin";
+        public const string Shopify = nameof(Shopify);
     }
 }
diff --git a/BTCPayServer/bundleconfig.json b/BTCPayServer/bundleconfig.json
index a87a91893..31e41a3fe 100644
--- a/BTCPayServer/bundleconfig.json
+++ b/BTCPayServer/bundleconfig.json
@@ -205,5 +205,12 @@
         "minify": {
             "enabled": false
         }
-    }  
+    },
+    {
+        "outputFileName": "wwwroot/bundles/shopify-bundle.min.js",
+        "inputFiles": [
+            "wwwroot/modal/btcpay.js",
+            "wwwroot/shopify/btcpay-shopify.js"
+        ]
+    }
 ]
diff --git a/BTCPayServer/wwwroot/modal/btcpay.js b/BTCPayServer/wwwroot/modal/btcpay.js
index 15a972b81..14a64d69f 100644
--- a/BTCPayServer/wwwroot/modal/btcpay.js
+++ b/BTCPayServer/wwwroot/modal/btcpay.js
@@ -40,7 +40,7 @@
     iframe.style.width = '100%';
     iframe.style.zIndex = '2000';
 
-    var origin = 'http://slack.btcpayserver.org join us there, and initialize this with your origin url through setApiUrlPrefix';
+    var origin = 'http://chat.btcpayserver.org join us there, and initialize this with your origin url through setApiUrlPrefix';
     var scriptMatch = thisScript.match(scriptSrcRegex)
     if (scriptMatch) {
         // We can't just take the domain as btcpay can run under a sub path with RootPath
@@ -56,6 +56,7 @@
 
     var onModalWillEnterMethod = function () { };
     var onModalWillLeaveMethod = function () { };
+    var onModalReceiveMessageMethod = function (event) { };
 
     function showFrame() {
         if (window.document.getElementsByName('btcpay').length === 0) {
@@ -80,6 +81,10 @@
         onModalWillLeaveMethod = customOnModalWillLeave;
     }
 
+    function onModalReceiveMessage(customOnModalReceiveMessage) {
+        onModalReceiveMessageMethod = customOnModalReceiveMessage;
+    }
+
     function receiveMessage(event) {
         var uri;
 
@@ -101,6 +106,7 @@
                 window.location = uri;
             }
         }
+        onModalReceiveMessageMethod(event);
     }
 
     function showInvoice(invoiceId, params) {
@@ -134,7 +140,8 @@
         showInvoice: showInvoice,
         onModalWillEnter: onModalWillEnter,
         onModalWillLeave: onModalWillLeave,
-        setApiUrlPrefix: setApiUrlPrefix
+        setApiUrlPrefix: setApiUrlPrefix,
+        onModalReceiveMessage: onModalReceiveMessage
     };
 
 })();
diff --git a/BTCPayServer/wwwroot/shopify/btcpay-browser-client.js b/BTCPayServer/wwwroot/shopify/btcpay-browser-client.js
deleted file mode 100644
index d73aa9804..000000000
--- a/BTCPayServer/wwwroot/shopify/btcpay-browser-client.js
+++ /dev/null
@@ -1,88 +0,0 @@
-/* Based on @djseeds script: https://github.com/btcpayserver/btcpayserver/issues/36#issuecomment-633109155 */
-/*** Creates a new BTCPayServer Modal
- * @param url - BTCPayServer Base URL
- * @param storeId - BTCPayServer store ID
- * @param data - Data to use for invoice creation
-* @returns - A promise that resolves when invoice is paid.
-* ***/
-var BtcPayServerModal = (function () {
-    function waitForPayment(btcPayServerUrl, invoiceId, storeId) {
-        // Todo: mutex lock on btcpayserver modal.
-        return new Promise(function (resolve, reject) {
-            // Don't allow two modals at once.
-            if (waitForPayment.lock) {
-                resolve(null);
-            }
-            else {
-                waitForPayment.lock = true;
-            }
-            window.btcpay.onModalWillEnter(function () {
-                var interval = setInterval(function () {
-                    getBtcPayInvoice(btcPayServerUrl, invoiceId, storeId)
-                        .then(function (invoice) {
-                            if (invoice.status == "complete") {
-                                clearInterval(interval);
-                                resolve(invoice);
-                            }
-                        })
-                        .catch(function (err) {
-                            clearInterval(interval);
-                            reject(err);
-                        });
-                }, 1000);
-                window.btcpay.onModalWillLeave(function () {
-                    waitForPayment.lock = false;
-                    clearInterval(interval);
-                    // If user exited the payment modal,
-                    // indicate that there was no error but invoice did not complete.
-                    resolve(null);
-                });
-            });
-            window.btcpay.showInvoice(invoiceId);
-        });
-    }
-
-    function getBtcPayInvoice(btcPayServerUrl, invoiceId, storeId) {
-        const url = btcPayServerUrl + "/invoices/" + invoiceId + "?storeId=" + storeId;
-        return fetch(url, {
-            method: "GET",
-            mode: "cors", // no-cors, cors, *same-origin,
-            headers: {
-                "Content-Type": "application/json",
-                "accept": "application/json",
-            }
-        })
-            .then(function (response) {
-                return response.json();
-            })
-            .then(function (json) {
-                return json.data;
-            })
-    }
-
-    return {
-        show: function (url, storeId, data) {
-            const path = url + "/invoices?storeId=" + storeId;
-            return fetch(path,
-                {
-                    method: "POST",
-                    mode: "cors",
-                    headers: {
-                        "Content-Type": "application/json",
-                        "accept": "application/json",
-                    },
-                    body: JSON.stringify(data)
-                }
-            )
-                .then(function (response) {
-                    return response.json();
-                })
-                .then(function (response) {
-                    return waitForPayment(url, response.data.id, storeId);
-                });
-        },
-        hide: function () {
-            window.btcpay.hideFrame();
-        }
-    }
-})()
diff --git a/BTCPayServer/wwwroot/shopify/btcpay-shopify-checkout.js b/BTCPayServer/wwwroot/shopify/btcpay-shopify-checkout.js
deleted file mode 100644
index 54203f898..000000000
--- a/BTCPayServer/wwwroot/shopify/btcpay-shopify-checkout.js
+++ /dev/null
@@ -1,138 +0,0 @@
-/* Based on @djseeds script: https://github.com/btcpayserver/btcpayserver/issues/36#issuecomment-633109155 */
-
-/*
- 
-1. In your BTCPayServer store you need to check "Allow anyone to create invoice"
-2. In Shopify Settings > Payment Providers > Manual Payment Methods add one which contains "Bitcoin with BTCPayServer"
-3. In Shopify Settings > Checkout > Additional Scripts input the following script, with the details from your BTCPayServer instead of the placeholder values.
-<script>
-    const BTCPAYSERVER_URL = "FULL_BTCPAYSERVER_URL_WITH_HTTPS";
-    const STORE_ID = "YOUR_BTCPAY_STORE_ID";
-</script>
-<script src="FULL_BTCPAYSERVER_URL_WITH_HTTPS/modal/btcpay.js"></script>
-<script src="FULL_BTCPAYSERVER_URL_WITH_HTTPS/shopify/btcpay-browser-client.js"></script>
-<script src="FULL_BTCPAYSERVER_URL_WITH_HTTPS/shopify/btcpay-shopify-checkout.js"></script>
-
- */
-
-! function () {
-    // extracted from shopify initialized page
-    const shopify_price = Shopify.checkout.payment_due;
-    const shopify_currency = Shopify.checkout.currency;
-
-    "use strict";
-    const pageElements = document.querySelector.bind(document),
-        insertElement = (document.querySelectorAll.bind(document),
-            (e,
-                n) => {
-                n.parentNode.insertBefore(e,
-                    n.nextSibling)
-            });
-
-    let pageItems = {},
-        pageheader = "Thank you!",
-        buttonElement = null;
-
-    const setPageItems = () => {
-        pageItems = {
-            mainHeader: pageElements("#main-header"),
-            orderConfirmed: pageElements(".os-step__title"),
-            orderConfirmedDescription: pageElements(".os-step__description"),
-            continueButton: pageElements(".step__footer__continue-btn"),
-            checkMarkIcon: pageElements(".os-header__hanging-icon"),
-            orderStatus: pageElements(".os-header__title"),
-            paymentMethod: pageElements(".payment-method-list__item__info"),
-            price: pageElements(".payment-due__price"),
-            finalPrice: pageElements(".total-recap__final-price"),
-            orderNumber: pageElements(".os-order-number"),
-        }
-    }
-
-    const orderPaid = () => {
-        pageItems.mainHeader.innerText = pageheader,
-            pageItems.orderConfirmed && (pageItems.orderConfirmed.style.display = "block"),
-            pageItems.orderConfirmedDescription && (pageItems.orderConfirmedDescription.style.display = "block"),
-            pageItems.continueButton && (pageItems.continueButton.style.visibility = "visible"),
-            pageItems.checkMarkIcon && (pageItems.checkMarkIcon.style.visibility = "visible"),
-            buttonElement && (buttonElement.style.display = "none");
-    };
-
-    window.setOrderAsPaid = orderPaid,
-        window.openBtcPayShopify = function waitForPaymentMethod() {
-            if (setPageItems(), "Order canceled" === pageItems.orderStatus.innerText) {
-                return;
-            }
-
-            const paymentMethod = pageItems.paymentMethod;
-
-            if (null === paymentMethod) {
-                return void setTimeout(() => {
-                    waitForPaymentMethod();
-                }, 10);
-            }
-
-            if (-1 === paymentMethod.innerText.toLowerCase().indexOf("bitcoin")) return;
-
-            // If payment method is bitcoin, display instructions and payment button.
-            pageheader = pageItems.mainHeader.innerText,
-                pageItems.mainHeader && (pageItems.mainHeader.innerText = "Review and pay!"),
-                pageItems.continueButton && (pageItems.continueButton.style.visibility = "hidden"),
-                pageItems.checkMarkIcon && (pageItems.checkMarkIcon.style.visibility = "hidden"),
-                pageItems.orderConfirmed && (pageItems.orderConfirmed.style.display = "none"),
-                pageItems.orderConfirmedDescription && (pageItems.orderConfirmedDescription.style.display = "none");
-
-            const orderId = pageItems.orderNumber.innerText.replace("Order #", "");
-
-            const url = BTCPAYSERVER_URL + "/invoices" + "?storeId=" + STORE_ID + "&orderId=" + orderId + "&status=complete";
-
-            // Check if already paid.
-            fetch(url, {
-                method: "GET",
-                mode: "cors", // no-cors, cors, *same-origin,
-                headers: {
-                    "Content-Type": "application/json",
-                    "accept": "application/json",
-                },
-            })
-                .then(function (response) {
-                    return response.json();
-                })
-                .then(function (json) {
-                    return json.data;
-                })
-                .then(function (data) {
-                    if (data.length != 0) {
-                        orderPaid();
-                    }
-                });
-
-            window.waitForPayment = function () {
-                buttonElement.innerHTML = "<span>Displaying Invoice...</span>";
-                BtcPayServerModal.show(
-                    BTCPAYSERVER_URL,
-                    STORE_ID,
-                    {
-                        price: shopify_price,
-                        currency: shopify_currency,
-                        orderId: orderId
-                    }
-                )
-                    .then(function (invoice) {
-                        buttonElement.innerHTML = payButtonHtml;
-                        if (invoice != null) {
-                            orderPaid();
-                        }
-                    });
-            }
-
-            // Payment button that opens modal
-            const payButtonHtml = '<button class="" onclick="window.waitForPayment()" style="width:210px; border: none; outline: none;"><img src="' + BTCPAYSERVER_URL + '/img/paybutton/pay.svg"></button>';
-
-            buttonElement = document.createElement("div");
-            buttonElement.innerHTML = payButtonHtml;
-            insertElement(buttonElement, pageItems.orderConfirmed);
-
-        }
-
-    window.openBtcPayShopify();
-}();
diff --git a/BTCPayServer/wwwroot/shopify/btcpay-shopify.js b/BTCPayServer/wwwroot/shopify/btcpay-shopify.js
new file mode 100644
index 000000000..2ba40d764
--- /dev/null
+++ b/BTCPayServer/wwwroot/shopify/btcpay-shopify.js
@@ -0,0 +1,170 @@
+window.BTCPayShopifyIntegrationModule = function () {
+    const pageElements = document.querySelector.bind(document);
+    const insertElement = (document.querySelectorAll.bind(document),
+        (e,
+            n) => {
+            n.parentNode.insertBefore(e,
+                n.nextSibling)
+        });
+
+    // execute BTCPayShopifyIntegrationModule as soon as possible
+    var paymentMethod = pageElements(".payment-method-list__item__info");
+    if (null === paymentMethod) {
+        return void setTimeout(() => {
+            window.BTCPayShopifyIntegrationModule();
+        }, 10);
+    }
+
+    if (!window.btcpay) {
+        throw new Error("The BTCPay modal js was not loaded on this page.");
+    }
+    if (!window.Shopify) {
+        throw new Error("The Shopify global object was not loaded on this page.");
+    }
+    if (!window.BTCPAYSERVER_URL || !window.STORE_ID) {
+        throw new Error("The BTCPAYSERVER_URL STORE_ID global vars were not set on this page.");
+    }
+    const shopify_order_id = Shopify.checkout.order_id;
+    const btcPayServerUrl = window.BTCPAYSERVER_URL;
+    const storeId = window.STORE_ID;
+    var currentInvoiceData;
+    var modalShown = false;
+
+    let buttonElement = null;
+
+    var pageItems = {
+        mainHeader: pageElements("#main-header"),
+        orderConfirmed: pageElements(".os-step__title"),
+        orderConfirmedDescription: pageElements(".os-step__description"),
+        continueButton: pageElements(".step__footer__continue-btn"),
+        checkMarkIcon: pageElements(".os-header__hanging-icon"),
+        orderStatus: pageElements(".os-header__title"),
+        paymentMethod: pageElements(".payment-method-list__item__info"),
+        price: pageElements(".payment-due__price"),
+        finalPrice: pageElements(".total-recap__final-price"),
+        orderNumber: pageElements(".os-order-number"),
+    };
+
+    function setOrderAsPaid() {
+        document.title = document.title.replace("Review and pay!", "Thank you!");
+        pageItems.mainHeader.innerText = "Thank you!",
+        pageItems.orderConfirmed && (pageItems.orderConfirmed.style.display = "block"),
+        pageItems.orderConfirmedDescription && (pageItems.orderConfirmedDescription.style.display = "block"),
+        pageItems.continueButton && (pageItems.continueButton.style.visibility = "visible"),
+        pageItems.checkMarkIcon && (pageItems.checkMarkIcon.style.visibility = "visible"),
+        buttonElement && (buttonElement.style.display = "none");
+    }
+
+    function showPaymentInstructions() {
+        document.title = document.title.replace("Thank you!", "Review and pay!");
+        pageItems.mainHeader && (pageItems.mainHeader.innerText = "Review and pay!"),
+        pageItems.continueButton && (pageItems.continueButton.style.visibility = "hidden"),
+        pageItems.checkMarkIcon && (pageItems.checkMarkIcon.style.visibility = "hidden"),
+        pageItems.orderConfirmed && (pageItems.orderConfirmed.style.display = "none"),
+        pageItems.orderConfirmedDescription && (pageItems.orderConfirmedDescription.style.display = "none");
+    }
+
+    function getOrCheckInvoice(backgroundCheck) {
+        const url = btcPayServerUrl + "/stores/" + storeId + "/integrations/shopify/" + shopify_order_id+"?amount="+Shopify.checkout.payment_due+ (backgroundCheck ? "&checkonly=true" : "");
+        return fetch(url, {
+            method: "GET",
+            mode: "cors", // no-cors, cors, *same-origin,
+            headers: {
+                "Content-Type": "application/json",
+                "accept": "application/json",
+            }
+        })
+            .then(function (response) {
+                return response.json();
+            }).catch(function () {
+                if (!backgroundCheck)
+                    alert("Could not initiate BTCPay Server payment method, try again later.");
+            })
+    }
+
+    function onPayButtonClicked() {
+        buttonElement.innerHTML = "<span>Displaying Invoice...</span>";
+
+        getOrCheckInvoice().then(handleInvoiceData).catch(fail.bind(this));
+    }
+
+    function handleInvoiceData(data, opts) {
+        currentInvoiceData = data;
+        if (!currentInvoiceData) {
+            if (modalShown) {
+                window.btcpay.hideFrame();
+                fail();
+            }else if(opts && opts.backgroundCheck){
+                injectPaymentButtonHtml();
+            }else{
+                fail();
+            }
+            return;
+        }
+        if (["complete", "confirmed", "paid"].indexOf(currentInvoiceData.status.toLowerCase()) >= 0) {
+            setOrderAsPaid();
+        } else if (["invalid", "expired"].indexOf(currentInvoiceData.status.toLowerCase()) >= 0) {
+            fail();
+        } else if (!opts || !opts.backgroundCheck) {
+            showModal();
+        } 
+    }
+
+    function showModal() {
+        if (currentInvoiceData && !modalShown) {
+            modalShown = true;
+            window.btcpay.setApiUrlPrefix(btcPayServerUrl);
+
+            window.btcpay.onModalReceiveMessage(function (evt) {
+                if (evt && evt.invoiceId && evt.status) {
+                    currentInvoiceData = evt;
+                }
+            });
+
+            window.btcpay.onModalWillEnter(function () {
+                modalShown = true;
+            });
+
+            window.btcpay.onModalWillLeave(function () {
+                modalShown = false;
+                getOrCheckInvoice(true).then(function (d) {
+                    buttonElement.innerHTML = payButtonHtml;
+                    handleInvoiceData(d, {backgroundCheck: true})
+                });
+            });
+            window.btcpay.showInvoice(currentInvoiceData.invoiceId);
+        }
+    }
+
+    function fail() {
+        currentInvoiceData = null;
+        buttonElement.innerHTML = payButtonHtml;
+    }
+
+    const payButtonHtml = '<button class="" onclick="onPayButtonClicked()" style="width:210px; border: none; outline: none;"><img src="' + btcPayServerUrl + '/img/paybutton/pay.svg"></button>';
+
+    function injectPaymentButtonHtml() {
+        // Payment button that opens modal
+        buttonElement = document.getElementById("btcpayserver-pay");
+        if (buttonElement) {
+            return;
+        }
+        buttonElement = document.createElement("div");
+        buttonElement.id = "btcpayserver-pay";
+        buttonElement.innerHTML = payButtonHtml;
+        insertElement(buttonElement, pageItems.orderConfirmed);
+    }
+
+    if (["bitcoin", "btc", "btcpayserver", "btcpay server"].filter(value => pageItems.paymentMethod.innerText.toLowerCase().indexOf(value) !== -1).length === 0) {
+        return;
+    }
+    showPaymentInstructions();
+    window.onPayButtonClicked = onPayButtonClicked.bind(this);
+    getOrCheckInvoice(true).then(function (d) {
+        injectPaymentButtonHtml();
+        handleInvoiceData(d, {backgroundCheck: true})
+    });
+
+};
+
+window.BTCPayShopifyIntegrationModule();