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To embed the signing interface in your web app, first get a ceremony URL.

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The ceremony URL

Add two query parameters to the ceremony URL:
  • embedded=true -> Configures the UI for embedding and specifies allowed sources for the frame-ancestors directive of the .
  • event_delivery=message -> Sends ceremony events (like ceremony completion) as Javascript messages.
Example URL with both query parameters:
https://sign.signatureapi.com/en/start?token=eyJhbGciOiJFUzI1NiIsInR5cCI6IkpXVCJ9.eyJpYXQiOjE3MjI4OTE3NDYsImV4cCI6MTcyMzQ5NjU0NiwiY2VyZW1vbnlf&embedded=true&event_delivery=message

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The <iframe> tag

Embed the signing interface using an iframe tag with the Ceremony URL as the src attribute.
Ensure you use the URL with the embedded=true and event_delivery=message query parameters appended.
<iframe
  id="signatureapi-ceremony"
  title="SignatureAPI Signing Ceremony"
  width="800"
  height="600"
  src="https://sign.signatureapi.com/en/start?token=eyJhbGciOiJFUzI1NiIsInR5cCI6IkpXVCJ9.eyJpYXQiOjE3MjI4OTE3NDYsImV4cCI6MTcyMzQ5NjU0NiwiY2VyZW1vbnlf&embedded=true&event_delivery=message">
</iframe>

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Testing with Embedder

To help you test ceremony embedding before implementing it in your application, we provide an Embedder tool. This tool allows you to quickly preview how your ceremony will appear inside an iframe.
Embedder tool interface showing ceremony URL input and iframe preview
To use the embedder, follow these steps:
  1. Go to the Embedder Tool
  2. Enter your ceremony URL (the embedded=true and event_delivery=message query parameters are added automatically)
  3. Optionally, adjust the width and height values in pixels
  4. The tool will display your ceremony in an iframe with the specified dimensions

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Listening to events

The embedded ceremony sends JavaScript MessageEvents for events happening inside the ceremony. Your app can listen to these events and take actions, such as closing the iframe when the ceremony is completed. Here’s an example of how to listen to these events: 
// Function to handle the ceremony completed event
function handleCeremonyCompleted(event) {
    console.log("Ceremony completed successfully.");
}

// Function to handle the ceremony canceled event
function handleCeremonyCanceled(event) {
    console.log("Ceremony was canceled by the user.");
}

// Function to handle the ceremony failed event
function handleCeremonyFailed(event) {
    const { error_type, error_message } = event.data;
    console.error(`Ceremony failed with error: ${error_type} - ${error_message}`);
}

// Function to handle incoming message events
function handleMessage(event) {
    const { type } = event.data;

    switch (type) {
        case 'ceremony.completed':
            handleCeremonyCompleted(event);
            break;
        case 'ceremony.canceled':
            handleCeremonyCanceled(event);
            break;
        case 'ceremony.failed':
            handleCeremonyFailed(event);
            break;
        default:
            console.warn(`Unknown event type: ${type}`);
    }
}

// Add event listener to window for message events
window.addEventListener('message', handleMessage, false);

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Troubleshooting

If the browser refuses to load the iframe content and you see an error like this in the console log:
Refused to frame … because an ancestor violates the following Content Security Policy directive: “frame-ancestors none”.
Make sure:
  1. You added the &embedded=true query parameter to the ceremony URL.
  2. Your app’s domain is included in the embeddable_in array when creating the ceremony.
To troubleshoot problems, you can try adding a wildcard to the embeddable_in array, for example: 
POST https://api.signatureapi.com/v1/recipients/re_5m393QvSqy9SasSmSIG5xS/ceremony HTTP/1.1
Content-Type: application/json
X-API-Key: key_test_...

{
  "authentication": [
    //...
  ],
  "embeddable_in": [
    "*"
  ]
}
We don’t recommend using the asterisk * wildcard in production, as it can create security vulnerabilities.