Signature API

This is a simple API for generating signatures with Google Fonts API and OpenType.js.

Live Demo

Prerequisites

• Node.js
• pnpm (or npm, ofc)
• Google Fonts API Key

Installation

1. Clone the repository

git clone https://github.com/onurravli/signature-api.git

2. Install dependencies:

pnpm install

3. Copy .env.example to .env and set your Google Fonts API key:

GOOGLE_FONTS_API_KEY=your_api_key_here

API Endpoints

Generate Signature

Generate a signature in SVG or PNG format.

Endpoint: POST /api/v1/signature

Request Body Parameters:

Parameter	Type	Required	Default	Description
name	string	Yes	-	The text to convert into signature
font	string	Yes	-	Google Font family name
color	string	Yes	-	Color in any valid CSS format (hex, rgb, etc.)
fontSize	number	No	72	Font size in pixels
fontWeight	number or string	Yes	-	Font weight (e.g., 400, 700, "regular", "bold")
padding	number	No	20	Padding around the signature in pixels
apiKey	string	No	-	Google Fonts API key (optional if set in .env)
response	string	No	-	Response format: "svg", "png", or both if empty

Example Request:

{
  "name": "John Doe",
  "font": "Dancing Script",
  "color": "#000000",
  "fontSize": 72,
  "fontWeight": 400,
  "padding": 20,
  "response": "svg"
}

Example Response:

For SVG response:

{
  "svg": "<svg>...</svg>"
}

For PNG response:

{
  "png": "data:image/png;base64,..."
}

For default response (both formats):

{
  "svg": "<svg>...</svg>",
  "png": "data:image/png;base64,...",
  "width": 300,
  "height": 150,
  "name": "John Doe",
  "font": "Dancing Script",
  "color": "#000000",
  "fontSize": 72,
  "fontWeight": 400,
  "padding": 20
}

Error Handling

The API returns appropriate HTTP status codes and error messages:

• 200 OK: Request successful
• 500 Internal Server Error: Server-side error with error message in response

Error Response Format:

{
  "error": "Error message description"
}

Development

1. Start the development server:

pnpm dev

2. Build for production:

pnpm build

3. Start production server:

pnpm start

License

MIT License. See LICENSE.md for more details.