Overview
Create and send documents for signing from your own system, with the NextSign API.
The NextSign API lets your system create a signing case — a title, the people who must sign, and the documents they sign — and hands you back a signing link for each recipient. Everything you create appears in the NextSign dashboard, and fires the same webhooks as work started there.
Beta. The behaviour described here is stable, but the surface is still small and details may change before general availability. The gaps are listed at the bottom of this page.
Base URL
https://api.nextsign.dk/v3/apiWhat you can do today
| Endpoint | Status |
|---|---|
POST /v3/api/cases — create and send a case | Available |
GET /v3/api/cases — list your cases | Available |
GET /v3/api/cases/{id} — retrieve one case | Available |
GET /v3/api/documents — list your document library | Available |
GET /v3/api/documents/{id} — a document and the fields it needs filled | Available |
POST /v3/api/documents/{id}/cases — fill a library document and send it | Available |
| Update and delete cases | Not yet |
| Uploading to and managing the document library; forms | Not yet |
What to expect
Requests fail loudly. Unknown fields are rejected rather than ignored, and every problem in the body comes back in one response, each with a field path pointing at the value that caused it.
A 2xx means the case exists. You never get an error for a case that was already created. If sending fails you still get 201, plus a per-channel delivery report — so a retry is always safe, and a briefly unavailable mail server never leaves you with two cases.
Responses are explicit. Every response is a defined object with a documented set of fields, so you can rely on what is there and on what is not.
Keys are real credentials. They are generated from a CSPRNG, stored hashed, and support revocation and expiry. See Authorization.
Where to start
1. Authorization
Create a key, send it, and understand why some keys are rejected.
2. Create a Case
A copy-paste quickstart, then the full request and response reference.
3. Errors
The error envelope, every slug, and what is safe to retry.
Not available yet
Being explicit about the gaps, so you can plan around them:
- No rate limiting is applied yet. Do not treat that as a licence to hammer the API; a limit is coming.
- No idempotency key. Retrying a
201creates a second case. Retry only on network failures and5xx, never on a4xx. - Scopes are not enforced. Every key currently has full access to its company. Per-key scopes are planned; keys issued today will keep working when they arrive.
- No search when listing cases. You can filter by state, folder, reference and creation date, but not by title or recipient. Filter on your own
referenceIdinstead. - The document library is read-only. You can list documents, read their fields and create cases from them, but uploading a new template or version still happens in the dashboard.