SignetX API Documentation

The SignetX API lets you generate legal contracts programmatically using AI. Bring your own OpenAI or Anthropic API key — you control your AI costs.

BYOK

Use your own AI keys. We never charge you for generation.

Fast

Contracts generated in under 10 seconds.

20+ Templates

NDAs, MSAs, SOWs, employment, and more.

Quick Start

1. Create a developer account at /signup
2. Add your OpenAI or Anthropic API key in the dashboard (select your preferred model)
3. Create an app to get your X-Developer-Key
4. Start making API requests

Authentication

Every API request must include your developer key in the X-Developer-Key header. You get this key when you create an app in the developer dashboard.

# All requests require the X-Developer-Key header
curl https://api.signetx.net/api/v1/generate \
  -H "X-Developer-Key: sk_signet_dev_xxxxx" \
  -H "Content-Type: application/json" \
  -d '{"template_slug": "nda", "fields": {}}'

Important: Never expose your developer key in client-side code or public repositories. Always proxy requests through your backend server.

POST/api/v1/generate

Generate a Contract

Generate a legal contract from a template using AI. The request uses your own AI key (OpenAI or Anthropic) that you configured in the dashboard.

Request Body

Parameter	Type	Required	Description
template_slug	string	Yes	Template to use (e.g. "nda", "msa")
fields	object	Yes	Key-value pairs for template variables
ai_provider	string	No	"openai" or "anthropic" (default: your active key)
format	string	No	"text", "html", or "both" (default: "both")

Example (JavaScript)

// Generate a contract
const response = await fetch(
  "https://api.signetx.net/api/v1/generate",
  {
    method: "POST",
    headers: {
      "X-Developer-Key": "sk_signet_dev_xxxxx",
      "Content-Type": "application/json",
    },
    body: JSON.stringify({
      template_slug: "nda",
      fields: {
        party_a: "Acme Inc.",
        party_b: "TechCorp LLC",
        effective_date: "2026-01-15",
        jurisdiction: "California",
      },
    }),
  }
);

const { contract, metadata } = await response.json();
// contract.id — use to retrieve later
// contract.content — the generated contract text
// contract.html — formatted HTML version
// metadata.tokens_used — AI tokens consumed

Example (Python)

import requests

response = requests.post(
    "https://api.signetx.net/api/v1/generate",
    headers={
        "X-Developer-Key": "sk_signet_dev_xxxxx",
        "Content-Type": "application/json",
    },
    json={
        "template_slug": "nda",
        "fields": {
            "party_a": "Acme Inc.",
            "party_b": "TechCorp LLC",
            "effective_date": "2026-01-15",
        },
    },
)

data = response.json()
print(data["contract"]["content"])

Response

{
  "contract": {
    "id": "ctr_abc123",
    "content": "MUTUAL NON-DISCLOSURE AGREEMENT\n\nThis Agreement...",
    "html": "<h1>Mutual Non-Disclosure Agreement</h1>...",
    "template_slug": "nda",
    "created_at": "2026-01-15T10:30:00Z"
  },
  "metadata": {
    "tokens_used": 1200,
    "ai_provider": "openai",
    "generation_time_ms": 8500
  }
}

GET/api/v1/templates

List Available Templates

Returns the list of templates available to your app. This is determined by the template scoping you configured when creating the app.

// List available templates for your app
const response = await fetch(
  "https://api.signetx.net/api/v1/templates",
  {
    headers: {
      "X-Developer-Key": "sk_signet_dev_xxxxx",
    },
  }
);

const { templates } = await response.json();
// templates: [
//   { slug: "nda", name: "NDA", category: "legal" },
//   { slug: "msa", name: "Master Service Agreement", category: "legal" },
//   ...
// ]

Response

{
  "templates": [
    {
      "slug": "nda",
      "name": "Non-Disclosure Agreement",
      "category": "legal",
      "fields": ["party_a", "party_b", "effective_date", "jurisdiction"]
    },
    {
      "slug": "msa",
      "name": "Master Service Agreement",
      "category": "legal",
      "fields": ["client", "provider", "term_months", "payment_terms"]
    }
  ]
}

GET/api/v1/contracts/:id

Retrieve a Contract

Fetch a previously generated contract by its ID. Returns the full content in both plain text and HTML formats.

// Retrieve a previously generated contract
const response = await fetch(
  "https://api.signetx.net/api/v1/contracts/${id}",
  {
    headers: {
      "X-Developer-Key": "sk_signet_dev_xxxxx",
    },
  }
);

const { contract } = await response.json();
// contract.content — plain text
// contract.html — formatted HTML
// contract.metadata — template info, fields used

EMBED/embed/:appId

Embeddable Widget

Drop a single iframe into your app to give your users a fully branded contract creation experience. The widget uses your developer AI key and respects your template scoping.

<!-- Embed the SignetX widget in your app -->
<iframe
  src="https://api.signetx.net/embed/APP_ID"
  width="100%"
  height="600"
  frameborder="0"
  style="border-radius: 12px; border: 1px solid #e0e0e0;"
></iframe>

Customization

- Branding: Set custom colors, logo, and title in your app settings
- Templates: Choose which templates appear in the widget
- Theme: Light or dark mode

WEBHOOKEvent notifications

Webhooks

Configure a webhook URL in your app settings to receive real-time notifications when contracts are generated, signed, or updated.

Supported Events

contract.generatedFired when a contract is successfully generated

contract.signedFired when a contract is signed by a party

contract.updatedFired when a contract is edited or amended

app.rate_limitedFired when your app hits its daily rate limit

Payload Example

// Webhook payloads are sent as POST to your configured URL

// contract.generated
{
  "event": "contract.generated",
  "app_id": "APP_ID",
  "contract_id": "CONTRACT_ID",
  "template_slug": "nda",
  "timestamp": "2026-01-15T10:30:00Z",
  "data": {
    "content_length": 4500,
    "tokens_used": 1200,
  }
}

// contract.signed
{
  "event": "contract.signed",
  "app_id": "APP_ID",
  "contract_id": "CONTRACT_ID",
  "timestamp": "2026-01-15T11:00:00Z",
  "data": {
    "signed_by": "user@example.com",
  }
}

Webhook Security

Each webhook includes an X-SignetX-Signature header containing an HMAC-SHA256 signature of the payload using your developer key. Always verify this signature on your server.

Error Codes

The API uses standard HTTP status codes.

Code	Meaning
400	Bad request — missing or invalid parameters
401	Unauthorized — invalid or missing X-Developer-Key
403	Forbidden — template not allowed for your app
429	Rate limited — daily request limit exceeded
500	Server error — AI generation failed
503	AI provider unavailable — check your API key

Error Response Format

{
  "error": {
    "code": "rate_limited",
    "message": "Daily request limit of 100 exceeded. Resets at midnight UTC.",
    "details": {
      "limit": 100,
      "used": 100,
      "resets_at": "2026-01-16T00:00:00Z"
    }
  }
}

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