Reference

Changelog

Notable changes to the public API, webhooks, SDKs and evidence features. Changes within /api/v1 are additive; see versioning.

2026-10: Dedicated API host#

The API is now served on https://api.sign.yt/v1. It accepts API keys only (browser session cookies are ignored). https://sign.yt/api/v1 keeps working; the Python and TypeScript SDKs default to the new host from 0.2.1. Conventions

API keys can be restricted to IPv4/IPv6 addresses and CIDR ranges. Other callers get 403 ip_not_allowed; empty list = any address. Restrict a key to IP addresses

Breaking for clients that read detail.code: detail is now always the same string as message (the 422 field-error list is unchanged). Branch on the top-level code and show message, which every error has always carried; error-specific data that used to sit inside detail is in extra. Errors
GET /documents/{id}/intake returns 204 when the document has no recipient start form (was 404 intake_not_found).

Didit identity provider (ID document + selfie with liveness, worldwide) alongside Authologic and login.gov.pl, with a manual-review status IN_REVIEW. Identity verification
GET /documents/{id} returns verification_type and each recipient's latest check as recipients[].identity_verification (status and provider only).
New webhook recipient.identity_verification_updated. Webhook events
Senders are emailed when a signer's check is declined or abandoned; the review-result email to the signer now includes their signing link.

Remote MCP endpoint /api/v1/mcp (Streamable HTTP, API-key auth, scope-filtered tools) and a new place_signature_fields tool. MCP server
redirect_url_after_sign on document create, template use, bulk send and campaigns, plus PATCH /documents/{id}; optional org allowlist of redirect domains. Redirect after signing
Embedded signing (Business+): /embed/sign/<token> framable by the org's allowed origins, with postMessage events. Embedding

Unified error envelope on every error: code, message, detail (legacy), request_id and optional extra. Errors
Cursor pagination for GET /documents and GET /webhooks/{id}/deliveries via cursor, X-Next-Cursor and Link: rel="next"; offset keeps working. Pagination
Rate-limit headers X-RateLimit-Limit, X-RateLimit-Remaining, X-RateLimit-Reset on API-key responses. Rate limits
New webhook emissions: document.viewed (first open of a signing link) and document.signed (each signature). Payload schemas documented for every event. Webhook events
New developer docs at docs.sign.yt with a self-hosted API reference.

Public verification links on verify.sign.yt/<code>, printed as a QR code on the certificate of completion.
OpenTimestamps (Bitcoin) anchoring of completed documents and a downloadable evidence bundle (GET /documents/{id}/evidence.zip).
Post-quantum evidence seal v2 (ML-DSA-65 + Ed25519), downloadable with GET /documents/{id}/pq-seal.
PAdES time-stamping with a fallback list of timestamp authorities; B-LTA platform seal when a TSA is available.
Explicit signing consent recorded with every signature; hardened audit and signature hash chains.

POST /documents/{id}/cancel takes a reason, notifies everyone involved and can create a corrected draft (copy_as_draft); emits document.cancelled.
PATCH /documents/{id}/recipients/{recipient_id} corrects a recipient's email, name or phone.
GET /documents/{id}/recipients/{recipient_id}/signing-link returns a pending recipient's signing link (audited).
Plan feature gating for API keys and webhooks (402 feature_not_in_plan).

Webhook deliveries with HMAC-SHA256 signatures over timestamp and body, retries with backoff and a dead-letter state; SSRF protection for webhook URLs.
Idempotency-Key support on unsafe methods and capped pagination on list endpoints.
PAdES platform seal with RFC 3161 timestamps.