API Reference
Signbee is a document signing API built for AI agents. One API call sends a document for two-party e-signing — both parties sign, both receive a SHA-256 certified PDF.
Authentication
Signbee supports two modes. You can start using the API immediately without an API key.
With API key
Sender is pre-verified. Recipient gets the signing email immediately. Best for automated agent workflows.
Without API key
Sender verifies via email OTP first. No signup or account needed to get started.
Authorization: Bearer YOUR_API_KEY
Get your API key at signb.ee/dashboard
Endpoints
/api/v1/sendSend a document for two-party e-signing. Provide either markdown or a PDF URL.
Auth: Optional — Bearer token or email OTP
Required fields
recipient_name— Full name of the recipientrecipient_email— Email address of the recipientmarkdown— Document content (min 10 chars, max 50KB)Or use pdf_url instead of markdown to send an existing PDF
Required without API key
sender_name— Full name of the sendersender_email— Email address of the senderOptional fields
title— Document title (auto-extracted from first heading)expires_in_days— Days until signing link expires (default: 7)curl -X POST https://signb.ee/api/v1/send \
-H "Content-Type: application/json" \
-H "Authorization: Bearer YOUR_API_KEY" \
-d '{
"markdown": "# Mutual NDA\n\nThis agreement...",
"recipient_name": "Bob Smith",
"recipient_email": "bob@acme.com"
}'{
"document_id": "cmm...",
"status": "pending_recipient",
"sender": "Alice Chen",
"recipient": "Bob Smith",
"expires_at": "2026-03-19T12:00:00.000Z"
}/api/v1/generateGenerate a PDF from markdown without initiating a signing flow. Useful for previewing documents.
Auth: Not required
Required fields
markdown— Document content (min 10 chars, max 50KB)curl -X POST https://signb.ee/api/v1/generate \
-H "Content-Type: application/json" \
-d '{"markdown": "# Invoice\n\nAmount: $500"}'{
"document_id": "cmm...",
"url": "https://signb.ee/view/cmm...",
"expires_at": "2026-03-16T12:00:00.000Z"
}/api/v1/documents/{id}Get the current status, signing URLs, and PDF links for a document.
Auth: Required — Bearer token
{
"document_id": "cmm...",
"status": "pending_recipient",
"title": "Mutual NDA",
"sender": { "name": "Alice Chen", "signed_at": "..." },
"recipient": { "name": "Bob Smith", "signed_at": null },
"original_pdf_url": "...",
"signed_pdf_url": null,
"signing_url": "https://signb.ee/sign/...",
"expires_at": "...",
"created_at": "..."
}/api/v1/documents/{id}Revoke a pending document. The signing link becomes invalid.
Auth: Required — Bearer token
{
"success": true,
"message": "Document revoked. The signing link is no longer valid."
}How the Signing Flow Works
- 01Agent calls
POST /api/v1/sendwith document content and party details - 02With API key: sender is pre-verified, recipient gets signing email immediately
- 03Without API key: sender verifies via OTP, then recipient gets signing email
- 04Recipient clicks link, reviews the document, and signs
- 05Both parties receive the signed PDF with SHA-256 certificate via email
Agent Integrations
MCP Server
Works with Claude Desktop, Cursor, Windsurf, and any MCP-compatible client.
{
"mcpServers": {
"signbee": {
"command": "npx",
"args": ["-y", "signbee-mcp"],
"env": { "SIGNBEE_API_KEY": "YOUR_API_KEY" }
}
}
}npm: signbee-mcp
Direct API
Call the REST API from any language. No SDK needed — just HTTP + JSON.
OpenAPI spec: signb.ee/openapi.json
Error Codes
| Code | Meaning |
|---|---|
| 400 | Missing or invalid fields |
| 401 | Invalid API key |
| 403 | Plan limit reached or unauthorized |
| 429 | Email rate limit — try again in a few minutes |
| 503 | Email service temporarily unavailable |
Questions?
hello@signb.eeLast updated: March 2026