diff --git a/BTCPayServer/Services/Shopify/OrderTransactionRegisterLogic.cs b/BTCPayServer/Services/Shopify/OrderTransactionRegisterLogic.cs
new file mode 100644
index 000000000..eab6bca34
--- /dev/null
+++ b/BTCPayServer/Services/Shopify/OrderTransactionRegisterLogic.cs
@@ -0,0 +1,57 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using Newtonsoft.Json.Linq;
+
+namespace BTCPayServer.Services.Shopify
+{
+    public class OrderTransactionRegisterLogic
+    {
+        private readonly ShopifyApiClient _client;
+
+        public OrderTransactionRegisterLogic(ShopifyApiClient client)
+        {
+            _client = client;
+        }
+
+        public async Task<dynamic> Process(string orderId, string currency = null, string amountCaptured = null)
+        {
+            dynamic resp = await _client.TransactionsList(orderId);
+
+            JArray transactions = resp.transactions;
+            if (transactions != null && transactions.Count >= 1)
+            {
+                dynamic transaction = transactions[0];
+
+                if (currency != null && currency.Equals(transaction.currency, StringComparison.OrdinalIgnoreCase))
+                {
+                    // 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 createTransaction = new TransactionCreate
+                {
+                    transaction = new TransactionCreate.DataHolder
+                    {
+                        parent_id = transaction.id,
+                        currency = transaction.currency,
+                        amount = amountCaptured ?? transaction.amount,
+                        kind = "capture",
+                        gateway = "BTCPayServer",
+                        source = "external"
+                    }
+                };
+
+                dynamic createResp = await _client.TransactionCreate(orderId, createTransaction);
+                return createResp;
+            }
+
+            return null;
+        }
+    }
+}
diff --git a/BTCPayServer/Services/Shopify/ShopifyOrderMarkerHostedService.cs b/BTCPayServer/Services/Shopify/ShopifyOrderMarkerHostedService.cs
new file mode 100644
index 000000000..c6d429304
--- /dev/null
+++ b/BTCPayServer/Services/Shopify/ShopifyOrderMarkerHostedService.cs
@@ -0,0 +1,89 @@
+using System;
+using System.Collections.Generic;
+using System.Globalization;
+using System.Linq;
+using System.Net.Http;
+using System.Text;
+using System.Threading;
+using System.Threading.Tasks;
+using BTCPayServer.Data;
+using BTCPayServer.Logging;
+using BTCPayServer.Services.Invoices;
+using BTCPayServer.Services.Stores;
+using Microsoft.Extensions.Hosting;
+using Microsoft.Extensions.Logging;
+using NBXplorer;
+
+namespace BTCPayServer.Services.Shopify
+{
+    public class ShopifyOrderMarkerHostedService : IHostedService
+    {
+        private readonly EventAggregator _eventAggregator;
+        private readonly StoreRepository _storeRepository;
+        private readonly IHttpClientFactory _httpClientFactory;
+
+        public ShopifyOrderMarkerHostedService(EventAggregator eventAggregator, StoreRepository storeRepository, IHttpClientFactory httpClientFactory)
+        {
+            _eventAggregator = eventAggregator;
+            _storeRepository = storeRepository;
+            _httpClientFactory = httpClientFactory;
+        }
+
+        private CancellationTokenSource _Cts;
+        private readonly CompositeDisposable leases = new CompositeDisposable();
+
+        public Task StartAsync(CancellationToken cancellationToken)
+        {
+            _Cts = CancellationTokenSource.CreateLinkedTokenSource(cancellationToken);
+
+            leases.Add(_eventAggregator.Subscribe<Events.InvoiceEvent>(async b =>
+            {
+                var invoice = b.Invoice;
+                var shopifyOrderId = invoice.Metadata?.OrderId;
+                if (invoice.Status == Client.Models.InvoiceStatus.Paid && shopifyOrderId != null)
+                {
+                    var storeData = await _storeRepository.FindStore(invoice.StoreId);
+                    var storeBlob = storeData.GetStoreBlob();
+
+                    if (storeBlob.Shopify?.IntegratedAt.HasValue == true)
+                    {
+                        var client = createShopifyApiClient(storeBlob.Shopify);
+
+                        try
+                        {
+                            var logic = new OrderTransactionRegisterLogic(client);
+                            await logic.Process(shopifyOrderId, invoice.Currency, invoice.Price.ToString(CultureInfo.InvariantCulture));
+                            Logs.PayServer.LogInformation("Registered order transaction on Shopify. " +
+                                $"Triggered by invoiceId: {invoice.Id}, Shopify orderId: {shopifyOrderId}");
+                        }
+                        catch (Exception ex)
+                        {
+                            Logs.PayServer.LogError(ex, $"Shopify error while trying to register order transaction. " +
+                                $"Triggered by invoiceId: {invoice.Id}, Shopify orderId: {shopifyOrderId}");
+                        }
+                    }
+                }
+            }));
+            return Task.CompletedTask;
+        }
+
+        private ShopifyApiClient createShopifyApiClient(StoreBlob.ShopifyDataHolder shopify)
+        {
+            return new ShopifyApiClient(_httpClientFactory, null, new ShopifyApiClientCredentials
+            {
+                ShopName = shopify.ShopName,
+                ApiKey = shopify.ApiKey,
+                ApiPassword = shopify.Password,
+                SharedSecret = shopify.SharedSecret
+            });
+        }
+
+        public Task StopAsync(CancellationToken cancellationToken)
+        {
+            _Cts?.Cancel();
+            leases.Dispose();
+
+            return Task.CompletedTask;
+        }
+    }
+}