Getting started with Express
Start accepting x402 payments in your Express server in 2 minutes.You can find the full code for this example here.
Step 1: Create a new server from the starter template
Use your favorite package manager:npm (npx)
pnpm
bun
Step 2: Set your environment variables
Open your generated project’s.env and set:
Step 3: Preview the server code
This is theindex.ts the starter generates. It loads your env, applies the x402 payment middleware, defines example routes, and logs the server URL.
Step 4: Run the server
Your server is now accepting 402 payments!
Step 5: Test the server
You can test payments against your server locally by following the fetch example or the axios example.Going to production
The starter works on the free tier out of the box — no API keys required. When you’re ready for production, create a merchant account at merchant.payai.network, get your API keys, and add them to your.env:
@payai/facilitator package automatically detects these environment variables and authenticates your requests to the facilitator. See Facilitator Pricing for tier details and Facilitator Authentication for the full protocol reference.
x402 reference
For a deeper dive into message shapes, headers, verification and settlement responses, see the x402 Reference.Need help?
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