How to monetize an API with x402 in under 10 minutes

If your endpoint is already live, you're 90% of the way there. x402 is middleware — it sits in front of your handler and gates it on payment.

1. Pick a wallet and network

Create a Base wallet (Coinbase Wallet, Rainbow, or a smart wallet). This is where USDC from buyers will land. Copy the address.

2. Add x402 middleware

Reference implementations exist for Express, Hono, FastAPI, and most other server frameworks. The middleware takes your price, destination wallet, and network, returns 402 to unpaid requests, and verifies payments on paid ones.

3. List on a marketplace

Submit the endpoint to Vend402 with a slug, tagline, category, sample response, and price in USDC. Buyers and agents will discover it through the catalog and the public transaction ledger.

4. Watch the ledger

Every paid call shows up in the public transactions table — proof to other providers that the marketplace has real demand, and proof to you that your endpoint is earning.

Pricing guidance

• Cheap data (FX rates, weather): $0.001 – $0.01 per call.
• Premium data (sentiment, scraping, enrichment): $0.01 – $0.10.
• LLM / inference / heavy compute: $0.05 – $1.00+.

Start low, watch volume, raise prices once you have signal. Unlike subscriptions, you can re-price per request at any time.