E-Signing API

The E-Signing API lets your application do what your team does in the app: turn a template into a signature request, send it, and follow it through to a signed, audit-trailed PDF — without anyone opening BunnyDoc.

It's a small, focused REST API. JSON in, JSON out, one bearer token, and the exact same permissions your team already has in the app.

How authentication works

Access is a two-step flow, and it's the first thing you'll build. Your long-lived API key is sent once to get a short-lived access token; every other request carries only the token, so the key never travels again.

Build it in this order

A complete integration is five calls. Follow them in this order and you'll hit the gotchas in the cheapest possible place — a 404 on a template you can read, not a 422 on a send you meant to deliver.

Endpoints at a glance

Each request is authorised by both the scope on your key and the permission of the user who owns it — a key can never do more than that person can in the app.

Want to be notified when a document is signed, declined or voided instead of polling? Use webhooks — and take the finished PDF straight from the envelope.document_ready payload.

Conventions

• JSON in, JSON out — send and expect application/json.
• Scoped to your company — every resource belongs to one company, and requests never cross company boundaries.
• Same permissions as the app — a key can only do what its owner's role allows. See Users & roles.
• Scopes narrow access — the scopes on a key (templates:read, contacts:read, contacts:write, envelopes:send, webhooks:read, webhooks:write, users:read) can only ever restrict what its owner could already do, never extend it.

Pagination

List endpoints take page (from 1) and per_page (up to 100, default 25), and return a pagination object:

{
  "data": [ /* … */ ],
  "pagination": { "page": 1, "per_page": 25, "total": 134, "total_pages": 6 }
}

Quotas

Reads are free of charge against your plan. Two things are metered:

• Sending draws on a separate API signature requests allowance — one unit per envelope, no matter how many recipients it has. This is not the same pool as envelopes sent from the app. When it's exhausted, sends return 402 quota_exceeded and nothing is delivered.
• Creating a contact consumes your plan's ordinary contact allowance, returning 403 quota_exceeded when full. You don't need to create contacts to send to people, so this is easy to avoid.

Check both under Settings → Billing → Resources.

Rate limits

Requests are throttled per API key (the token endpoint is per IP). Exceeding a limit returns 429 rate_limited with a standard Retry-After header, in seconds — back off for that long and retry.

Counting per key (not per IP) means a shared egress address — an integration platform, a NAT — never makes one customer's traffic count against another's.

Errors

Every error has the same shape — branch on error.code, never on the message text. See the full error reference.

{
  "error": {
    "code": "unknown_signer_role",
    "message": "…",
    "details": { },
    "reference": "0190f3a2-7b6c-7e21-9a3f-2c9b1d4e5f60"
  }
}

reference appears on the errors we log server-side (5xx and 422). Keep it in your own logs — quoting it to support locates the exact failure in one lookup.

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