diff --git a/BTCPayServer/Controllers/InvoiceController.UI.cs b/BTCPayServer/Controllers/InvoiceController.UI.cs
index aa266603e..d29269307 100644
--- a/BTCPayServer/Controllers/InvoiceController.UI.cs
+++ b/BTCPayServer/Controllers/InvoiceController.UI.cs
@@ -174,7 +174,8 @@ namespace BTCPayServer.Controllers
         [AcceptMediaTypeConstraint("application/bitcoin-paymentrequest", false)]
         [XFrameOptionsAttribute(null)]
         [ReferrerPolicyAttribute("origin")]
-        public async Task<IActionResult> Checkout(string invoiceId, string id = null, string paymentMethodId = null)
+        public async Task<IActionResult> Checkout(string invoiceId, string id = null, string paymentMethodId = null,
+            [FromQuery]string view = null)
         {
             //Keep compatibility with Bitpay
             invoiceId = invoiceId ?? id;
@@ -185,6 +186,8 @@ namespace BTCPayServer.Controllers
             if (model == null)
                 return NotFound();
 
+            if (view == "modal")
+                model.IsModal = true;
 
             _CSP.Add(new ConsentSecurityPolicy("script-src", "'unsafe-eval'")); // Needed by Vue
             if (!string.IsNullOrEmpty(model.CustomCSSLink) &&
diff --git a/BTCPayServer/Models/InvoicingModels/PaymentModel.cs b/BTCPayServer/Models/InvoicingModels/PaymentModel.cs
index 8f1dffeaa..34fa52f3e 100644
--- a/BTCPayServer/Models/InvoicingModels/PaymentModel.cs
+++ b/BTCPayServer/Models/InvoicingModels/PaymentModel.cs
@@ -21,6 +21,7 @@ namespace BTCPayServer.Models.InvoicingModels
         public string CustomLogoLink { get; set; }
         public string DefaultLang { get; set; }
         public List<AvailableCrypto> AvailableCryptos { get; set; } = new List<AvailableCrypto>();
+        public bool IsModal { get; set; }
         public bool IsLightning { get; set; }
         public string CryptoCode { get; set; }
         public string ServerUrl { get; set; }
diff --git a/BTCPayServer/Views/Invoice/Checkout-Body.cshtml b/BTCPayServer/Views/Invoice/Checkout-Body.cshtml
index 7f7502ffb..40bf5ab4b 100644
--- a/BTCPayServer/Views/Invoice/Checkout-Body.cshtml
+++ b/BTCPayServer/Views/Invoice/Checkout-Body.cshtml
@@ -12,6 +12,9 @@
                 <img class="header__icon__img" src="~/img/logo-white.png" height="40">
             }
         </div>
+        <div class="close-icon close-action">
+            &#10006;
+        </div>
     </div>
     <div class="timer-row">
         <div class="timer-row__progress-bar" style="width: 0%;"></div>
@@ -326,9 +329,12 @@
                     </div>
                 </div>
                 <div class="success-message">{{$t("This invoice has been paid")}}</div>
-                <a class="action-button" :href="srvModel.merchantRefLink" v-show="srvModel.merchantRefLink">
+                <a class="action-button" :href="srvModel.merchantRefLink" v-show="srvModel.merchantRefLink && !isModal">
                     <span>{{$t("Return to StoreName", srvModel)}}</span>
                 </a>
+                <button class="action-button close-action" v-show="isModal">
+                    <span>{{$t("Return to StoreName", srvModel)}}</span>
+                </button>
             </div>
         </div>
         <div class="button-wrapper refund-address-form-container" id="refund-overpayment-button">
@@ -351,7 +357,7 @@
 
     <div class="bp-view expired" id="expired">
         <div>
-            <div class="expired__body">
+            <div class="expired__body" style="margin-bottom: 20px;">
                 <div class="expired__header">{{$t("What happened?")}}</div>
                 <div class="expired__text" i18n="">
                     {{$t("InvoiceExpired_Body_1", {storeName: srvModel.storeName, maxTimeMinutes: @Model.MaxTimeMinutes})}}
@@ -370,10 +376,12 @@
                     {{srvModel.orderId}}
                 </div>
             </div>
-            <a class="action-button" :href="srvModel.merchantRefLink" v-show="srvModel.merchantRefLink"
-               style="margin-top: 20px;">
+            <a class="action-button" :href="srvModel.merchantRefLink" v-show="srvModel.merchantRefLink && !isModal">
                 <span>{{$t("Return to StoreName", srvModel)}}</span>
             </a>
+            <button class="action-button close-action" v-show="isModal">
+                <span>{{$t("Return to StoreName", srvModel)}}</span>
+            </button>
         </div>
     </div>
 </div>
diff --git a/BTCPayServer/Views/Invoice/Checkout.cshtml b/BTCPayServer/Views/Invoice/Checkout.cshtml
index bc6a73fa0..b5425e871 100644
--- a/BTCPayServer/Views/Invoice/Checkout.cshtml
+++ b/BTCPayServer/Views/Invoice/Checkout.cshtml
@@ -27,10 +27,20 @@
         <link href="@Model.CustomCSSLink" rel="stylesheet" />
     }
 
-    <style type="text/css">
-    </style>
+    @if (Model.IsModal)
+    {
+        <style type="text/css">
+            body {
+                background: rgba(55, 58, 60, 0.4);
+            }
+
+            .close-icon {
+                display: flex;
+            }
+        </style>
+    }
 </head>
-<body style="background: #E4E4E4">
+<body>
     <noscript>
         <center style="padding: 2em">
             <h2>Javascript is currently disabled in your browser.</h2>
@@ -53,29 +63,29 @@
     </center>
     <![endif]-->
 
-<invoice>
-    <div class="no-bounce" id="checkoutCtrl" v-cloak>
-        <div class="modal page">
-            <div class="modal-dialog open opened enter-purchaser-email" role="document">
-                <div class="modal-content long">
-                    <div class="content">
-                        <div class="invoice">
-                            <partial name="Checkout-Body" />
+    <invoice>
+        <div class="no-bounce" id="checkoutCtrl" v-cloak>
+            <div class="modal page">
+                <div class="modal-dialog open opened enter-purchaser-email" role="document">
+                    <div class="modal-content long">
+                        <div class="content">
+                            <div class="invoice">
+                                <partial name="Checkout-Body" />
+                            </div>
                         </div>
                     </div>
-                </div>
 
-                <div style="margin-top: 10px; text-align: center;">
-                    @* Not working because of nsSeparator: false, keySeparator: false,
+                    <div style="margin-top: 10px; text-align: center;">
+                        @* Not working because of nsSeparator: false, keySeparator: false,
                             {{$t("nested.lang")}} >>
                         *@
-                    <select class="cmblang reverse invisible" onchange="changeLanguage($(this).val())">
-                        @foreach (var lang in langService.GetLanguages())
-                        {
-                            <option value="@lang.Code">@lang.DisplayName</option>
-                        }
-                    </select>
-                    <script>
+                        <select class="cmblang reverse invisible" onchange="changeLanguage($(this).val())">
+                            @foreach (var lang in langService.GetLanguages())
+                            {
+                                <option value="@lang.Code">@lang.DisplayName</option>
+                            }
+                        </select>
+                        <script>
                         $(function() {
                             var storeDefaultLang = '@Model.DefaultLang';
                             if (urlParams.lang) {
@@ -96,10 +106,11 @@
                                 hoverIntent: 5000
                             });
                         }
-                    </script>
-                </div>
-                <div style="margin-top: 10px; text-align: center;" class="form-text small text-muted">
-                    <span>Powered by <a target="_blank" href="https://github.com/btcpayserver/btcpayserver">BTCPay Server</a></span>
+                        </script>
+                    </div>
+                    <div style="margin-top: 10px; text-align: center;" class="form-text small text-muted">
+                        <span>Powered by <a target="_blank" href="https://github.com/btcpayserver/btcpayserver">BTCPay Server</a></span>
+                    </div>
                 </div>
             </div>
         </div>
@@ -153,7 +164,7 @@
         // Ignoring custom HTML5 elements, eg: bp-spinner
         /^bp-/
     ];
-    
+
     var checkoutCtrl = new Vue({
         i18n: i18n,
         el: '#checkoutCtrl',
@@ -162,12 +173,13 @@
             changelly: ChangellyComponent
         },
         data: {
-                srvModel: srvModel,
-                lndModel: null,
-                scanDisplayQr: "",
-                expiringSoon: false
+            srvModel: srvModel,
+            lndModel: null,
+            scanDisplayQr: "",
+            expiringSoon: false,
+            isModal: '@(Model.IsModal ? "true" : "false")'
         }
     });
-</script>
+    </script>
 </body>
 </html>
diff --git a/BTCPayServer/wwwroot/checkout/css/normalizer.css b/BTCPayServer/wwwroot/checkout/css/normalizer.css
index 47545bd12..7e9e9fb2f 100644
--- a/BTCPayServer/wwwroot/checkout/css/normalizer.css
+++ b/BTCPayServer/wwwroot/checkout/css/normalizer.css
@@ -6,10 +6,6 @@ html {
     -webkit-text-size-adjust: 100%;
 }
 
-body {
-    margin: 0;
-}
-
 article,
 aside,
 details,
@@ -333,8 +329,9 @@ body {
     font-family: "Roboto", "Helvetica", sans-serif;
     font-size: 1rem;
     line-height: 1.5;
-    color: #373a3c;
     background-color: #fff;
+    margin: 0;
+    background: #E4E4E4;
 }
 
 [tabindex="-1"]:focus {
@@ -1296,10 +1293,6 @@ html {
     -webkit-text-size-adjust: 100%;
 }
 
-body {
-    margin: 0;
-}
-
 article,
 aside,
 details,
@@ -1619,14 +1612,6 @@ html {
     -webkit-tap-highlight-color: transparent;
 }
 
-body {
-    font-family: "Roboto", "Helvetica", sans-serif;
-    font-size: 1rem;
-    line-height: 1.5;
-    color: #373a3c;
-    background-color: #fff;
-}
-
 [tabindex="-1"]:focus {
     outline: none !important;
 }
@@ -9084,11 +9069,12 @@ strong {
 
 .close-icon {
     flex-grow: 1;
-    display: flex;
+    display: none;
     justify-content: flex-end;
     padding: 13px;
     transition: opacity 250ms ease;
     opacity: 1;
+    cursor: pointer;
 }
 
     .close-icon img {
@@ -10373,7 +10359,7 @@ All mobile class names should be prefixed by m- */
 }
 
 .paid:not(.paid-over) .status-icon {
-    padding-top: 54px;
+    padding-top: 45px;
 }
 
 .paid:not(.paid-over) .button-wrapper {
diff --git a/BTCPayServer/wwwroot/checkout/js/core.js b/BTCPayServer/wwwroot/checkout/js/core.js
index cc91f42de..da93e11ab 100644
--- a/BTCPayServer/wwwroot/checkout/js/core.js
+++ b/BTCPayServer/wwwroot/checkout/js/core.js
@@ -32,7 +32,6 @@ function changeCurrency(currency) {
 }
 
 function onDataCallback(jsonData) {
-
     var newStatus = jsonData.status;
 
     if (newStatus === "complete" ||
@@ -123,20 +122,6 @@ $(document).ready(function () {
     // initialize
     onDataCallback(srvModel);
 
-    /* TAF
-    
-    - Version mobile
-    
-    - Réparer le décallage par timer
-    
-    - Preparer les variables de l'API
-    
-    - Gestion des differents evenements en fonction du status de l'invoice
-    
-    - sécuriser les CDN
-    
-    */
-
     // check if the Document expired
     if (srvModel.expirationSeconds > 0) {
         progressStart(srvModel.maxTimeSeconds); // Progress bar
@@ -147,7 +132,19 @@ $(document).ready(function () {
             hideEmailForm();
     }
 
+    $(".close-action").on("click", function () {
+        $("invoice").fadeOut(300, function () {
+            window.parent.postMessage("close", "*");
+        });
+    });
 
+    window.parent.postMessage("loaded", "*");
+    jQuery("invoice").fadeOut(0);
+    jQuery("invoice").fadeIn(300);
+
+    // eof initialize
+
+    // FUNCTIONS
     function hideEmailForm() {
         $("#emailAddressView").removeClass("active");
         $("placeholder-refundEmail").html(srvModel.customerEmail);
diff --git a/BTCPayServer/wwwroot/modal/btcpay.js b/BTCPayServer/wwwroot/modal/btcpay.js
new file mode 100644
index 000000000..8ea852d89
--- /dev/null
+++ b/BTCPayServer/wwwroot/modal/btcpay.js
@@ -0,0 +1,117 @@
+/* jshint browser: true, strict: false, maxlen: false, maxstatements: false */
+(function () {
+    function warn() {
+        if (window.console && window.console.warn) {
+            window.console.warn.apply(window.console, arguments);
+        }
+    }
+
+    if (window.btcpay) {
+        warn('btcpay.js attempted to initialize more than once.');
+        return;
+    }
+
+    var iframe = document.createElement('iframe');
+    iframe.name = 'btcpay';
+    iframe.class = 'btcpay';
+    iframe.setAttribute('allowtransparency', 'true');
+    iframe.style.display = 'none';
+    iframe.style.border = 0;
+    iframe.style.position = 'fixed';
+    iframe.style.top = 0;
+    iframe.style.left = 0;
+    iframe.style.height = '100%';
+    iframe.style.width = '100%';
+    iframe.style.zIndex = '1000';
+
+    var origin = 'http://slack.btcpayserver.org join us there, and initialize this with your origin url through setApiUrlPrefix';
+    // urlPrefix should be site root without trailing slash
+    function setApiUrlPrefix(urlPrefix) {
+        origin = stripTrailingSlashes(urlPrefix);
+    }
+    function stripTrailingSlashes(site) {
+        return site.replace(/\/+$/, "");
+    } 
+
+    var onModalWillEnterMethod = function () { };
+    var onModalWillLeaveMethod = function () { };
+
+    function showFrame() {
+        if (window.document.getElementsByName('btcpay').length === 0) {
+            window.document.body.appendChild(iframe);
+        }
+        onModalWillEnterMethod();
+        iframe.style.display = 'block';
+    }
+
+    function hideFrame() {
+        onModalWillLeaveMethod();
+        iframe.style.display = 'none';
+        iframe = window.document.body.removeChild(iframe);
+    }
+
+    function onModalWillEnter(customOnModalWillEnter) {
+        onModalWillEnterMethod = customOnModalWillEnter;
+    }
+
+    function onModalWillLeave(customOnModalWillLeave) {
+        onModalWillLeaveMethod = customOnModalWillLeave;
+    }
+
+    function receiveMessage(event) {
+        var uri;
+
+        if (origin !== event.origin) {
+            return;
+        }
+        if (event.data === 'close') {
+            hideFrame();
+        } else if (event.data === 'loaded') {
+            showFrame();
+        } else if (event.data && event.data.open) {
+            uri = event.data.open;
+            if (uri.indexOf('bitcoin:') === 0) {
+                window.location = uri;
+            }
+        } else if (event.data && event.data.mailto) {
+            uri = event.data.mailto;
+            if (uri.indexOf('mailto:') === 0) {
+                window.location = uri;
+            }
+        }
+    }
+
+    function showInvoice(invoiceId, params) {
+        window.document.body.appendChild(iframe);
+        var invoiceUrl = origin + '/invoice?id=' + invoiceId + '&view=modal';
+        if (params && params.animateEntrance === false) {
+            invoiceUrl += '&animateEntrance=false';
+        }
+        iframe.src = invoiceUrl;
+    }
+
+    function setButtonListeners() {
+        var buttons = window.document.querySelectorAll('[data-btcpay-button]');
+        for (var i = 0; i < buttons.length; i++) {
+            var b = buttons[0];
+            b.addEventListener('submit', showFrame);
+        }
+    }
+
+    window.addEventListener('load', function load() {
+        window.removeEventListener('load', load);
+    });
+
+    window.addEventListener('message', receiveMessage, false);
+    setButtonListeners();
+
+    window.btcpay = {
+        showFrame: showFrame,
+        hideFrame: hideFrame,
+        showInvoice: showInvoice,
+        onModalWillEnter: onModalWillEnter,
+        onModalWillLeave: onModalWillLeave,
+        setApiUrlPrefix: setApiUrlPrefix
+    };
+
+})();
diff --git a/BTCPayServer/wwwroot/modal/test.html b/BTCPayServer/wwwroot/modal/test.html
new file mode 100644
index 000000000..43b2a6248
--- /dev/null
+++ b/BTCPayServer/wwwroot/modal/test.html
@@ -0,0 +1,11 @@
+<html>
+<head>
+    <script src="btcpay.js"></script>
+    <script type="text/javascript">
+        btcpay.setApiUrlPrefix("http://127.0.0.1:14142");
+    </script>
+</head>
+<body>
+    <button onclick="btcpay.showInvoice('25DKDgcB4z4PtkPJyHVYnV')">Open Modal</button>
+</body>
+</html>