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SignatureAPI lets you apply your company’s branding to each envelope individually. Branding covers the signing ceremony interface that recipients see and the emails sent to them throughout the signing process. In this guide, we will create an envelope with:
  • A company logo displayed in email headers and the signing ceremony.
  • An accent color applied to buttons and interactive elements.
  • A custom email footer for legal disclaimers or contact information.
Before creating the branded envelope, upload your logo to your account’s Library. Only files uploaded to your Library can be used as logos; external URLs are not supported. Your logo must meet the following requirements:
  • Format: PNG
  • Height: At least 160px (to avoid pixelation on high-resolution displays)
  • File size: Under 100KB
  • Background: Transparent works best, as logos appear against both white (emails) and gray (signing ceremony) backgrounds
Upload your logo using the Dashboard Library, or send it via the API: 
// POST https://api.signatureapi.com/v1/uploads
// X-API-Key: key_test_...
// Content-Type: image/png
// <raw binary file content>
The response includes a url property that looks like https://api.signatureapi.com/v1/uploads/upl_.... Copy this URL and use it as the value of the logo property when creating your envelope.

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Create a Branded Envelope

Include a branding object in your envelope creation request: 
// POST https://api.signatureapi.com/v1/envelopes
// X-API-Key: key_test_...
// Content-Type: application/json

{
    "title": "Service Agreement",
    "documents": [
        //...
    ],
    "recipients": [
        //...
    ],
    "branding": {
        "logo": "https://api.signatureapi.com/v1/uploads/upl_3jBYlxa9gv0fGLzFAnfwxe",
        "accent_color": "#9810fa",
        "email": {
            "footer": "**Disclaimer:** This email and its attachments may contain confidential information. If you are not the intended recipient, please delete it and notify the sender.",
            "logo_position": "left"
        }
    }
}

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Branding properties

logo The URL of the logo uploaded to your Library. The logo appears in the header of recipient emails and the signing ceremony. accent_color A hex color code applied to buttons in emails and the signing ceremony (for example, #9810fa). The color must meet a contrast ratio of at least 4.5:1 against white, following WCAG guidelines. If the submitted color does not meet this requirement, the API returns an error with a suggested compliant alternative. You can verify your color in advance using the WebAIM Color Contrast Checker. email.footer Text appended to the bottom of all recipient emails, after SignatureAPI’s standard footer. Use it for legal disclaimers, privacy notices, or contact information. Supports a subset of Markdown: **bold**, *italic*, and \n\n for paragraph breaks. email.logo_position Controls the horizontal alignment of the logo in email headers. Accepted values are left, center, and right. Defaults to left.
Branding applies to the signing ceremony interface and emails sent to recipients (signing requests and completed document delivery). It does not apply to internal notification emails sent to the account owner, or to the signed documents themselves.

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Try It

Try this example in Postman using your test API key to create a free, non-binding test envelope. Test envelopes won’t send emails, but you can review the branding in your dashboard.

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Keep Learning

  • Learn about the full branding object and visual examples of branding applied to emails and the signing ceremony.
  • Explore the uploads endpoint to learn more about uploading files via the API.