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Easy Sign API

Automate signature requests and verify documents with a single API call. Perfect for AI agents, scripts, and integrations.

Quick Start

1

Create an API Key

Go to Settings → API Keys and create a new key.

2

Prepare Your Document

Have a PDF ready (URL or base64 encoded). Max 2MB on Free / 4MB on Pro, up to 15 pages.

3

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:

HeaderDescription
Retry-AfterSeconds to wait before retrying (rounded up from the reset time)
X-RateLimit-RemainingRequests remaining in the current window (always 0 on a 429)
X-RateLimit-ResetUnix 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 5xx and 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 4xx only after fixing the underlying input — those are deterministic failures, not transient ones.
  • For HTTP 429, honor Retry-After with jittered exponential backoff.

Send Signature Request

POST/api/agent/sign-request

Create and send a signature request in a single call.

Request Example (cURL)

Request
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

ParameterTypeDescription
sender.emailstringSender's email address (required)
sender.namestringSender's name (optional)
recipient.emailstringRecipient's email address (required)
recipient.namestringRecipient's name (optional)
document.urlstringPublic URL to PDF document
document.base64stringBase64 encoded PDF content
document.file_namestringFile name (optional, auto-detected)
fieldsarrayArray of signature fields (required)
envelope_namestringCustom 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 field
  • signature_date - Signature with date
  • date - Date only

Position Presets

  • signature_bottom_right
  • signature_bottom_left
  • signature_bottom_center
  • date_after_signature
  • signature_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)

Response
{
  "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

Response
{
  "success": false,
  "error": {
    "code": "INVALID_EMAIL",
    "message": "Valid sender email is required"
  }
}

Verify Document

POST/api/verify

Verify the authenticity and integrity of signed documents. No authentication required (public API).

Verification Types

  • transaction_only - Verify Transaction ID exists in our records
  • full - Upload PDF for complete integrity check (SHA-256 hash comparison)

Request Example (JSON)

Request
curl -X POST https://easy-sign.ca/api/verify \
  -H "Content-Type: application/json" \
  -d '{ "transactionId": "ES-20241206-ABC12345" }'

Request Example (with File Verification)

Request
curl -X POST https://easy-sign.ca/api/verify \
  -F "file=@signed-document.pdf" \
  -F "transactionId=ES-20241206-ABC12345"

Request Parameters

ParameterTypeDescription
transactionIdstringTransaction ID (format: ES-YYYYMMDD-XXXXXXXX). Found on signed documents.
fileFileOptional: Upload the signed PDF for full integrity verification

Success Response (Full Verification)

Response
{
  "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

StatusDescription
validDocument is fully signed and verified. Integrity check passed (if file was uploaded).
pendingDocument exists but signing is not yet complete.
not_foundTransaction ID does not exist in our records.
tamperedFile has been modified. Hash does not match the original signed document.
voidedDocument was voided by the sender after creation and is no longer legally valid. Returned with verified: false.

Tampered Document Response

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.

Response
{
  "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:

.claude/commands/easy-sign.md
---
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:

MCP Tool Schema
{
  "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:

Terminal
# 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

CodeHTTPDescription
INVALID_FORMAT401API key missing or has wrong prefix
INVALID_API_KEY401API key not recognized
KEY_REVOKED401API key has been revoked by the owner
KEY_EXPIRED401API key has expired
QUOTA_EXCEEDED403Monthly envelope quota reached for your plan
RATE_LIMITED429Too many requests (default 10/minute per key, configurable)
INVALID_JSON400Request body is not valid JSON
INVALID_EMAIL400Email format is invalid
SAME_EMAIL400Sender and recipient are the same
DOCUMENT_TOO_LARGE400Document exceeds plan limit (2MB Free / 4MB Pro)
DOCUMENT_TOO_MANY_PAGES400Document exceeds 15 page limit
INVALID_PDF400Invalid or corrupted PDF
INVALID_URL400Document URL is malformed or unsafe (SSRF protection)
DOCUMENT_URL_FAILED400Failed to download from URL
INVALID_FILE_NAME400File name exceeds 255 characters
NO_FIELDS400No signature fields provided
INVALID_FIELD_TYPE400Field type must be signature, signature_date, or date
INVALID_FIELD_POSITION400Field position is invalid
STORAGE_EXCEEDED400Total storage limit reached for your plan
EMAIL_FAILED500Outbound signature email failed to send (request rolled back)
INTERNAL_ERROR500Unexpected 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.

StatusHTTPDescription
valid200Document signed and verified. With a file uploaded, hash integrity is also confirmed.
pending200Document exists but signing is incomplete
tampered200File hash does not match the original signed document
voided200Sender voided the document — no longer legally valid
not_found400Transaction ID format invalid (must be ES-YYYYMMDD-XXXXXXXX)
not_found404Transaction ID does not exist or refers to a deleted record
not_found500Internal 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

Need Help?

Have questions or need assistance? We're here to help.