Easy Sign API
Automate signature requests and verify documents with a single API call. Perfect for AI agents, scripts, and integrations.
Quick Start
Create an API Key
Go to Settings → API Keys and create a new key.
Prepare Your Document
Have a PDF ready (URL or base64 encoded). Max 2MB on Free / 4MB on Pro, up to 15 pages.
Send a Request
Call the API endpoint to create and send a signature request.
Authentication
All API requests require an API key passed in the Authorization header:
Authorization: Bearer es_live_your_api_key_here
Rate Limits & Retries
Rate Limit Headers
When you exceed your per-key rate limit, the API returns HTTP 429 with these headers so your client can back off correctly:
| Header | Description |
|---|---|
| Retry-After | Seconds to wait before retrying (rounded up from the reset time) |
| X-RateLimit-Remaining | Requests remaining in the current window (always 0 on a 429) |
| X-RateLimit-Reset | Unix epoch milliseconds when the rate-limit window resets |
Successful (2xx) responses currently do not include rate-limit headers — only the 429 response carries them. Plan your retry policy around Retry-After.
Idempotency & Retries
Important. POST /api/agent/sign-request has external side effects: it sends a real email to the recipient. Retrying a failed-but-actually-sent request will create a duplicate envelope and send a second email.
The API does not currently support an Idempotency-Key header. To stay safe:
- Treat HTTP
5xxand timeouts as uncertain, not failed — the email may have been sent. - Before retrying, check your dashboard or persist a client-side request hash to detect prior submission.
- Always retry
4xxonly after fixing the underlying input — those are deterministic failures, not transient ones. - For HTTP
429, honorRetry-Afterwith jittered exponential backoff.
Send Signature Request
/api/agent/sign-requestCreate and send a signature request in a single call.
Request Example (cURL)
curl -X POST https://easy-sign.ca/api/agent/sign-request \
-H "Authorization: Bearer es_live_your_api_key" \
-H "Content-Type: application/json" \
-d '{
"sender": {
"email": "me@example.com",
"name": "John Doe"
},
"recipient": {
"email": "client@example.com",
"name": "Jane Smith"
},
"document": {
"url": "https://example.com/contract.pdf"
},
"fields": [
{
"type": "signature",
"page": 1,
"preset": "signature_bottom_right"
},
{
"type": "date",
"page": 1,
"preset": "date_after_signature"
}
],
"envelope_name": "Contract Agreement"
}'Request Parameters
| Parameter | Type | Description |
|---|---|---|
| sender.email | string | Sender's email address (required) |
| sender.name | string | Sender's name (optional) |
| recipient.email | string | Recipient's email address (required) |
| recipient.name | string | Recipient's name (optional) |
| document.url | string | Public URL to PDF document |
| document.base64 | string | Base64 encoded PDF content |
| document.file_name | string | File name (optional, auto-detected) |
| fields | array | Array of signature fields (required) |
| envelope_name | string | Custom name for the envelope (optional) |
Field Configuration
Each field requires a type, page number, and position (using preset or custom coordinates).
Field Types
signature- Signature fieldsignature_date- Signature with datedate- Date only
Position Presets
signature_bottom_rightsignature_bottom_leftsignature_bottom_centerdate_after_signaturesignature_footer
For custom positioning, use the position object:
{
"type": "signature",
"page": 1,
"position": {
"x": 60, // X position (0-100%)
"y": 85, // Y position (0-100%)
"width": 25, // Width (1-50%)
"height": 8 // Height (1-20%)
}
}Success Response (HTTP 201 Created)
{
"success": true,
"envelope_id": "550e8400-e29b-41d4-a716-446655440000",
"signing_url": "https://easy-sign.ca/sign/550e8400...?token=abc123",
"expires_at": "<ISO 8601 timestamp, ~7 days from request time>",
"recipient_email": "client@example.com"
}A successful request returns HTTP 201. If non-critical post-send updates fail (e.g. envelope status flip), the response may include an optional warnings: string[] array — the email has already been sent and cannot be recalled, so treat warnings as advisory.
Error Response
{
"success": false,
"error": {
"code": "INVALID_EMAIL",
"message": "Valid sender email is required"
}
}Verify Document
/api/verifyVerify the authenticity and integrity of signed documents. No authentication required (public API).
Verification Types
transaction_only- Verify Transaction ID exists in our recordsfull- Upload PDF for complete integrity check (SHA-256 hash comparison)
Request Example (JSON)
curl -X POST https://easy-sign.ca/api/verify \
-H "Content-Type: application/json" \
-d '{ "transactionId": "ES-20241206-ABC12345" }'Request Example (with File Verification)
curl -X POST https://easy-sign.ca/api/verify \ -F "file=@signed-document.pdf" \ -F "transactionId=ES-20241206-ABC12345"
Request Parameters
| Parameter | Type | Description |
|---|---|---|
| transactionId | string | Transaction ID (format: ES-YYYYMMDD-XXXXXXXX). Found on signed documents. |
| file | File | Optional: Upload the signed PDF for full integrity verification |
Success Response (Full Verification)
{
"verified": true,
"transactionId": "ES-20241206-ABC12345",
"status": "valid",
"verificationType": "full",
"message": "Document verified successfully. File integrity confirmed - no modifications detected.",
"details": {
"envelopeName": "Contract Agreement",
"status": "completed",
"createdAt": "2024-12-06T10:00:00Z",
"completedAt": "2024-12-06T11:30:00Z",
"recipientCount": 1,
"signedCount": 1,
"documentCount": 1
}
}Status Values
| Status | Description |
|---|---|
| valid | Document is fully signed and verified. Integrity check passed (if file was uploaded). |
| pending | Document exists but signing is not yet complete. |
| not_found | Transaction ID does not exist in our records. |
| tampered | File has been modified. Hash does not match the original signed document. |
| voided | Document was voided by the sender after creation and is no longer legally valid. Returned with verified: false. |
Tampered Document Response
{
"verified": false,
"transactionId": "ES-20241206-ABC12345",
"status": "tampered",
"verificationType": "full",
"message": "Document has been modified. The uploaded file does not match the original signed document."
}GET /api/verify (Discovery)
A GET request to the same path returns endpoint metadata — useful for tooling that auto-discovers APIs.
{
"name": "Easy Sign Document Verification API",
"version": "1.0",
"description": "Verify the authenticity of documents signed via Easy Sign",
"usage": {
"method": "POST",
"contentType": "application/json or multipart/form-data",
"parameters": {
"transactionId": "The Transaction ID found on the document (format: ES-YYYYMMDD-XXXXXXXX)",
"file": "Optional: Upload the signed PDF file for verification"
}
},
"legal": {
"notice": "Documents signed via Easy Sign are legally binding under ESIGN Act, UETA, and eIDAS regulations.",
"auditTrail": "Complete audit trails are maintained for all signed documents."
}
}AI Skills Integration
Configure AI agents like Claude Code, MCP tools, or custom AI assistants to send signature requests on your behalf. Perfect for automating document workflows through natural language commands.
Claude Code Skill
Save the following as .claude/commands/easy-sign.md in your project or home directory:
---
name: send-signature-request
description: Send a document for electronic signature via Easy Sign API
---
# Send Signature Request
Use this skill when the user wants to send a PDF document for electronic signature.
## Prerequisites
- Easy Sign API key stored in $EASY_SIGN_API_KEY
- PDF document (URL or local file path)
## Usage
Call the Easy Sign API to send a signature request:
```bash
curl -X POST https://easy-sign.ca/api/agent/sign-request \
-H "Authorization: Bearer $EASY_SIGN_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"sender": { "email": "SENDER_EMAIL", "name": "SENDER_NAME" },
"recipient": { "email": "RECIPIENT_EMAIL", "name": "RECIPIENT_NAME" },
"document": { "url": "DOCUMENT_URL" },
"fields": [
{ "type": "signature", "page": 1, "preset": "signature_bottom_right" },
{ "type": "date", "page": 1, "preset": "date_after_signature" }
],
"envelope_name": "Document Name"
}'
```
## Response Handling
On success, return the `signing_url` to the user.
The recipient will receive an email notification.
Link expires in 7 days.MCP Tool Definition
Use this JSON schema to define an MCP tool for Easy Sign integration:
{
"name": "easy_sign_send_signature_request",
"description": "Send a PDF document for electronic signature. The recipient receives an email with a signing link.",
"inputSchema": {
"type": "object",
"properties": {
"sender": {
"type": "object",
"properties": {
"email": { "type": "string", "format": "email" },
"name": { "type": "string" }
},
"required": ["email"]
},
"recipient": {
"type": "object",
"properties": {
"email": { "type": "string", "format": "email" },
"name": { "type": "string" }
},
"required": ["email"]
},
"document": {
"type": "object",
"description": "Provide either url or base64 (max 2MB Free / 4MB Pro, up to 15 pages)",
"properties": {
"url": { "type": "string", "format": "uri" },
"base64": { "type": "string" },
"file_name": { "type": "string" }
}
},
"fields": {
"type": "array",
"minItems": 1,
"description": "Signature fields. At least one is required.",
"items": {
"type": "object",
"properties": {
"type": { "type": "string", "enum": ["signature", "signature_date", "date"] },
"page": { "type": "integer", "minimum": 1 },
"preset": {
"type": "string",
"enum": [
"signature_bottom_right",
"signature_bottom_left",
"signature_bottom_center",
"signature_footer",
"date_after_signature"
]
}
},
"required": ["type", "page"]
}
},
"envelope_name": { "type": "string", "description": "Custom envelope name (optional)" }
},
"required": ["sender", "recipient", "document", "fields"]
}
}Environment Setup
Store your API key securely in an environment variable:
# Add to your shell profile (~/.bashrc, ~/.zshrc, etc.) export EASY_SIGN_API_KEY="es_live_your_api_key_here"
Example Workflow
Here's how a conversation with an AI agent might look:
User
Send the contract at https://example.com/contract.pdf to john@example.com for signature. I'm jane@company.com.
AI Agent
I'll send that document for signature using Easy Sign...
Signature request sent successfully!
John (john@example.com) will receive an email with a link to sign the document. The link expires in 7 days.
Best Practices
- Confirm document and recipient details before sending
- Store API keys in environment variables, never hardcode
- Handle errors gracefully with clear feedback to users
- Use meaningful envelope names for easy tracking
Error Codes
Sign Request API
| Code | HTTP | Description |
|---|---|---|
| INVALID_FORMAT | 401 | API key missing or has wrong prefix |
| INVALID_API_KEY | 401 | API key not recognized |
| KEY_REVOKED | 401 | API key has been revoked by the owner |
| KEY_EXPIRED | 401 | API key has expired |
| QUOTA_EXCEEDED | 403 | Monthly envelope quota reached for your plan |
| RATE_LIMITED | 429 | Too many requests (default 10/minute per key, configurable) |
| INVALID_JSON | 400 | Request body is not valid JSON |
| INVALID_EMAIL | 400 | Email format is invalid |
| SAME_EMAIL | 400 | Sender and recipient are the same |
| DOCUMENT_TOO_LARGE | 400 | Document exceeds plan limit (2MB Free / 4MB Pro) |
| DOCUMENT_TOO_MANY_PAGES | 400 | Document exceeds 15 page limit |
| INVALID_PDF | 400 | Invalid or corrupted PDF |
| INVALID_URL | 400 | Document URL is malformed or unsafe (SSRF protection) |
| DOCUMENT_URL_FAILED | 400 | Failed to download from URL |
| INVALID_FILE_NAME | 400 | File name exceeds 255 characters |
| NO_FIELDS | 400 | No signature fields provided |
| INVALID_FIELD_TYPE | 400 | Field type must be signature, signature_date, or date |
| INVALID_FIELD_POSITION | 400 | Field position is invalid |
| STORAGE_EXCEEDED | 400 | Total storage limit reached for your plan |
| EMAIL_FAILED | 500 | Outbound signature email failed to send (request rolled back) |
| INTERNAL_ERROR | 500 | Unexpected server error — safe to retry after a short delay |
Verify API
The Verify API does not use the error.code envelope. Outcomes are conveyed via the status field plus the HTTP status code.
| Status | HTTP | Description |
|---|---|---|
| valid | 200 | Document signed and verified. With a file uploaded, hash integrity is also confirmed. |
| pending | 200 | Document exists but signing is incomplete |
| tampered | 200 | File hash does not match the original signed document |
| voided | 200 | Sender voided the document — no longer legally valid |
| not_found | 400 | Transaction ID format invalid (must be ES-YYYYMMDD-XXXXXXXX) |
| not_found | 404 | Transaction ID does not exist or refers to a deleted record |
| not_found | 500 | Internal server error. The body still carries status: 'not_found' for legacy reasons — treat this as a transient backend failure and retry with jittered exponential backoff. |
Limits
2 / 4 MB
Max file size (Free / Pro)
15
Max pages per document
1
Recipient per request
10/min
Rate limit per API key (configurable)
7 days
Signing link validity
5
API keys per user