API Documentation

The SignatureAI API lets you generate beautiful handwritten signatures programmatically. Integrate signature generation into your app with a single HTTP request.

Base URL

https://signatureai.ai/api/v1

Format

JSON (REST)

Version

v0.2.0

#Authentication

Authenticate requests by including your API key in the X-API-Key header. Free-tier requests (with watermark) don't require authentication.

X-API-Key: sk_live_your_api_key_here

🔐 Keep your API key secret

Never expose your API key in client-side code. Use it only from your backend server.

#Quick Start

Generate your first signature in under 30 seconds:

curl -X POST https://signatureai.ai/api/v1/generate \
  -H "Content-Type: application/json" \
  -H "X-API-Key: sk_live_your_key" \
  -d '{
    "name": "John Doe",
    "style": "elegant"
  }'

#Generate Signature

POST/generate

Generate a new signature. Returns download URLs for PNG and SVG formats.

Request Body

namestringrequired

The name or text to render (1–200 characters)

stylestring

Style preset — see /styles for options. Default: elegant

slantfloat

Slant angle override (-1.0 to 1.0)

pressurefloat

Pen pressure override (0.1 to 2.0)

sizefloat

Output size multiplier (0.5 to 3.0)

watermarkboolean

Include watermark. Default: true (auto-removed with valid API key)

Response

{
  "job_id": "job_a1b2c3d4e5f6",
  "status": "completed",
  "signature_id": "sig_x9y8z7w6v5u4",
  "png_url": "/download/sig_x9y8z7w6v5u4.png",
  "svg_url": "/download/sig_x9y8z7w6v5u4.svg",
  "generation_ms": 142
}

#List Styles

GET/styles

Returns all available signature styles with descriptions.

curl https://signatureai.ai/api/v1/styles

#Signatures CRUD

POST/signatures/save

Save a generated signature to your account for later retrieval.

GET/signatures

List saved signatures with pagination. Optional user_id, limit, offset query params.

curl "https://signatureai.ai/api/v1/signatures?limit=10&offset=0" \
  -H "X-API-Key: sk_live_your_key"

DELETE/signatures/{sig_id}

Permanently delete a saved signature. Returns 204 No Content on success.

#API Keys

POST/api-keys

Create a new API key. The full key is only returned once — store it securely.

curl -X POST https://signatureai.ai/api/v1/api-keys \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Production App",
    "scopes": ["signatures:generate", "signatures:read"],
    "expires_in_days": 365
  }'

Available Scopes

signatures:generatesignatures:readsignatures:deleteusage:read*

GET/api-keys

List all API keys with usage stats. Full key values are never returned.

DELETE/api-keys/{key_id}

Revoke an API key. Revoked keys cannot be used for authentication.

POST/api-keys/validate

Validate an API key and return its scopes. Send the key in the X-API-Key header.

#Rate Limits

Rate limits are applied per IP address on the /generate endpoint.

Tier	Limit	Window	Watermark
Free (no key)	100 requests	per minute	Yes
API Key (Pro)	Per-key limits	per minute	No

Rate limit headers are included in every response:

X-RateLimit-Limit: 100
X-RateLimit-Remaining: 87
X-RateLimit-Reset: 1708171260

#Error Codes

All errors return a consistent JSON structure:

{
  "detail": "Human-readable error message"
}

Status	Meaning	Common Causes
400	Bad Request	Invalid parameters, malformed JSON
401	Unauthorized	Missing or invalid API key
403	Forbidden	API key lacks required scope
404	Not Found	Resource doesn't exist
429	Rate Limited	Too many requests — slow down
500	Server Error	Internal error — retry with backoff
503	Unavailable	Model not loaded yet — retry shortly

Ready to get started?

Create your free account and generate your first signature in seconds.