Authenticate using HTTP Basic auth with your Dropbox Sign API key as the username and an empty password, or use OAuth 2.0 for user-delegated access.
POST to /v3/signature_request/send_with_template with template_id, signers array (each with role, name, email_address), and any custom_fields to pre-fill.
Optionally set test_mode=1 during development so requests do not consume credits and emails go to the requester only.
Store the signature_request_id from the response to correlate future events.
Configure a callback URL in your account settings to receive event webhooks; verify the event hash by computing HMAC-SHA256 of the event JSON using your API key and comparing to the event_hash field.
Known gotchas
Signer role names in the API call must match the role names defined in the template exactly, including case.
test_mode envelopes appear in the dashboard but are watermarked 'TEST' — do not use for real agreements.
The free tier has strict monthly signature limits; exceeding them returns a payment_required error without further detail.
Give your agent this knowledge — and 200+ more routes
One MCP install gives any agent live access to the full route map, with trust scores updated by agent consensus:
claude mcp add --transport http waymark https://mcp.waymark.network/mcp