402 API

Boilerplate for building out an api on the X402 payment protocol for monetizing API endpoints.

Live demo at 402api.com

API Endpoints

Edit and add API Endpoints in server.js and public/config.js The server exposes the following API endpoints (GET or POST):

/text-to-image

• Description: Generates an image based on a text prompt using OpenAI's DALL-E 3 model.
• Payment Required: Yes (e.g., $0.10 on Base network).
• Query Parameters:
  • prompt (string): The text prompt for image generation (defaults to "a beautiful landscape").
• Word Limit: The prompt is limited to a maximum of 10,000 words.
• Returns: JSON object with image URL and prompt.

/word-count

• Description: Counts the number of words in a given text.
• Payment Required: Yes (e.g., $0.01 on Base network).
• Request Body:
  • text (string): The text for which to count words.
• Word Limit: The input text is limited to a maximum of 10,000 words.
• Returns: JSON object with wordCount and original text.

/sentiment-analysis

• Description: Performs basic sentiment analysis on the provided text, classifying it as positive, negative, or neutral.
• Payment Required: Yes (e.g., $0.05 on Base network).
• Request Body:
  • text (string): The text to analyze.
• Word Limit: The input text is limited to a maximum of 10,000 words.
• Returns: JSON object with sentiment, original text, and scores (positive and negative word counts).

GET /

• Description: Serves the index.html page from the public directory.

Setup and Run Server

1. Install Dependencies:

   npm install
   # or
   yarn install
   

2. Environment Variables: Create a .env file in the root of the project with the following variables:

   # Your wallet address that will receive payments
   WALLET_ADDRESS=your_wallet_address_here
   
   # OpenAI API key for DALL-E image generation
   OPENAI_API_KEY=your_openai_api_key_here
   
   # CDP API key ID
   CDP_API_KEY_ID=your_cdp_api_key_id_here
   
   # CDP API key secret
   CDP_API_KEY_SECRET=your_cdp_api_key_secret_here
   

3. Start the Server:

   node server.js
   

   The server will start on http://localhost:4021.

Test Buy

1. Install Dependencies (if not already done):

   npm install
   # or
   yarn install
   

2. Environment Variables: Add the following to your .env file for testing buy:

   # Private key for the wallet (for testing buy)
   PRIVATE_KEY=0xPrivateKeyHere
   

3. Test Buy:

   node testBuy.js
   

Dependencies

• express: Web framework for Node.js.
• x402-express: Express middleware for X402 payments.
• @coinbase/x402: Facilitator for X402 protocol.
• dotenv: Loads environment variables from a .env file.
• openai: OpenAI Node.js library for accessing the DALL-E API.

Learn more about the 402 payment protocol at x402.org.