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You can customize the visual appearance of signing ceremonies and recipient emails by adding your company’s branding to individual envelopes. Each envelope can have its own branding configuration, including logo, accent colors, and email customization options. When you add branding to an envelope, it customizes:
  • The signing ceremony interface that recipients see
  • Emails sent to recipients throughout the signing process, like signing requests and completed document delivery emails.
It doesn’t customize:
  • Internal notification emails, like those sent to the account owner about envelope status changes.
  • Deliverables (signed documents)
See how these elements look in practice in the Visual examples section.

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Adding branding

Branding is configured individually for each envelope. Add branding by including a branding property when creating your envelope: 
// POST https://api.signatureapi.com/v1/envelopes
// X-API-Key: key_test_...
// Content-Type: application/json

{
    "title": "Dummy Consent",
    "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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Accent colors

The accent_color property controls the color of buttons in both emails and the signing ceremony. Specify colors using hex color codes (for example, #9810fa). You can see accent colors in action in the Visual examples section below.
The accent color is only applied to button styles. Other interactive elements, such as text input fields, checkboxes, or signature boxes, remain in their default colors (blue for normal states, red for error states). This ensures that color continues to convey important meaning, like indicating errors, without causing confusion for signers.

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Accessibility requirements

Your accent color must meet accessibility standards for contrast. Specifically, it needs a contrast ratio of at least 4.5:1 against white backgrounds and text, following Web Content Accessibility Guidelines (WCAG). If your color doesn’t meet these requirements, the API will return an error with a suggested compliant color that’s visually similar to your original choice.
Test your color’s contrast ratio using the WebAIM Color Contrast Checker before submitting your envelope.

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Company logos

Upload your logo file to display it in recipient emails and signing ceremonies. Your logo appears in the header area of both the email messages and the signing ceremony interface. Before adding your logo to an envelope:
  1. Upload to your Library: Go to your Dashboard Library and upload your logo file
  2. Copy the upload URL: After uploading, copy the resulting URL (it will look like https://api.signatureapi.com/v1/uploads/upl_...)
  3. Use the URL in your envelope: Include this URL in the logo property of your branding configuration
Only files uploaded to your account’s Library can be used as logos. Direct external URLs or temporary uploads are not supported.

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Logo requirements

Your logo file should meet these requirements:
  • Format: PNG
  • Height: At least 160px tall to prevent pixelation on high-resolution displays
  • File size: Under 100KB for optimal loading performance
  • Background: Transparent background works best since logos appear against different colored backgrounds
The logo displays against a white background in emails and a gray background in the signing ceremony interface. To see how logos appear in both contexts, check out the Visual examples section.

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Email customization

Beyond logo and accent color, you can further customize the emails sent to recipients using the email property within your branding configuration.

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Custom footers

Include additional information at the bottom of all recipient emails, such as legal disclaimers or company policies. Your custom footer appears after SignatureAPI’s standard footer content. This is particularly useful for:
  • Legal disclaimers required by your organization
  • Privacy notices and confidentiality statements
  • Contact information or support details

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Logo positioning

Control where your logo appears in the email header by setting the logo_position property. You can choose from:
  • left - Logo aligns to the left side of the email header
  • center - Logo centers in the email header
  • right - Logo aligns to the right side of the email header
The Visual examples section shows how left-positioned logos appear in recipient emails.

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Visual examples

The following examples show how branding appears across different parts of the signing process. These use an envelope with purple branding (#9810fa) and a left-positioned logo: 
// POST https://api.signatureapi.com/v1/envelopes
// X-API-Key: key_test_...
// Content-Type: application/json

{
    "title": "Dummy Consent",
    "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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Signature request email

When recipients receive their signing invitation, they’ll see your branding in the email:
Signature request email with custom branding applied

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Signing ceremony interface

During the signing process, recipients see your branding throughout the ceremony:
Signing ceremony interface with custom branding applied

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Completed document delivery email

After signing is complete, the delivery email also includes your branding:
Document delivery email with custom branding applied
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