API
Prefill document fields with the API
Supply default or read-only values for text, date, choice, file, image, and signature fields.
Developers12 minutes
Before you begin
- A scoped API key
- The template field names or schema
What you will complete
- A request whose known values are populated before signing
Map values to field names
Field names in the payload must match the template schema. Prefer stable machine-readable names when templates are part of an integration contract.
- Text and date fields accept normalized scalar values.
- Checkbox, radio, multiple, and select values must match configured options.
- File, image, and signature values may require an attachment upload or a supported base64 or remote URL input.
- Read-only values remain visible but cannot be edited by the signer.
Test the signer experience
- 1Create a test submissionDisable provider delivery or use a controlled recipient.
- 2Open the signing URLConfirm values appear on the correct page and belong to the correct signer.
- 3Check read-only fieldsVerify protected values cannot be changed.
- 4Complete and inspectDownload the PDF and confirm rendered values match the request payload.