Observers

An observer is a CC-style recipient on a signing request. They never sign; they get at most two emails:

1. On dispatch: when the first signer is invited: "X is collecting signatures on Y." No attachment and no link to the document. Not sent with send_emails: false, which silences this notice along with the invitations.
2. At completion: when every signer has signed: the final tamper-evident PDF + the audit certificate, which is always in English, as attachments — and no link. A signed PDF too large to attach (the email's attachments stay under about 30 MB) arrives instead as a link of the observer's own to that one signed document, which works for 30 days (and not after the workspace's retention deleted the document). Nothing is sent when a signer declined, was withdrawn or expired: such a document never completes.

Observers are workspace-scoped CCs, distinct from signers. They get no signing URL, no token, no field placement.

Adding observers

{
  "observer_emails": [
    "outside-counsel@law-firm.com",
    "compliance@acme.com"
  ]
}

Pass on POST /v1/signing-requests, the only create call that takes observers (instantiate and confirm do not). Up to 20 observers per document, counted before duplicates are removed; more entries are a 400 invalid_request. Each entry is a plain address string, at most 254 characters; there is no name or language per observer. Send addresses without surrounding spaces: they are checked before anything else happens, so " office@firm.ch", a display-name form ("Office" <office@firm.ch>) or a non-ASCII domain (send its xn--… punycode form) is a 400 invalid_request. Accepted addresses are lower-cased and de-duplicated, and the response's observers lists what was stored. The list cannot be changed after the create.

The request key is observer_emails; observers is only the response key. In a multipart body, send the array as a JSON-encoded string.

An observer who is also on the document

An address in observer_emails stays on the list even when it is also a signer or the document's sender (the user who created the API key). That person gets the dispatch notice next to their own invitation, but only one email at completion:

When are they emailed?

Language. Both observer emails are in the request's language: the request-level locale of the create, else your workspace language (Settings → Signing), else English. Never a signer's own locale: observers are other people, and one document can have signers in several languages (see Language per signer). Before 2026-10-19 the notice followed the first signer's language and "Completed" the completing signer's; a document created before then keeps that rule for its "Completed" email.

Treat document.completed, or GET /v1/documents/{id} → status: "signed", as the proof of completion, never the observer email. All three follow one rule: every signer signed.

Observers don't see real-time intermediate events, and there are no observer webhooks. If you want that level of detail, register a webhook: the workspace webhook fires signing_request.signed per signer, plus document.completed at the end.

Both observer emails are on the audit trail, with the addresses in meta.observers: observer_notified on the first invited signer's request and observer_completed on the completing signer's request (GET /v1/signing-requests/{id} → auditEvents). The audit certificate lists no observer addresses.

Use cases

• Outside counsel that needs the final signed contract for the firm's file.
• Compliance / risk that wants the audit certificate for an archive without becoming a signer.
• Account exec who needs a trigger to update the CRM but isn't party to the contract.
• A shared mailbox such as a secretariat: an observer is an address, not an account.

What observers don't do

• Sign: they receive emails, not signing URLs.
• Receive reminders, a note per signature, or a declined, withdrawn or expired notice.
• Place fields: every field is placed by the create call itself (anchor markers, explicit coordinates or an appended signature page; see Placement modes).
• Edit observers: once a signing request is dispatched the observer list is fixed for that document.