Sign a Signature Request on behalf of a given Signer.

Use this endpoint if you are integrating your own signing flow (Signers won't go through Yousign's pre-made signing flow).

To use this endpoint, you must match the following conditions:

• The Signature Request delivery_mode must be set to none.
• The Signature Request must not have any Approver, Signer Document Request or Signer Consent Request.
• The Signature Request must not have the parameter signers_allowed_to_decline set to true.
• The signature level must be "Simple eSignature".

Related guide: Building your own signing flow

ℹ️ This endpoint accepts two request body formats — pick the one that matches your use case:

• 📝 application/json — sign without uploading a signature image.
• 📁 multipart/form-data — upload a signature image alongside the consent payload.

🔓 Endpoint access

• Environments: production, sandbox
• API key scopes: organization, workspace
• Plans: scale
• Add-ons (for production access): none