How to charge AI agents for an API with HTTP 402, written for the developers doing it: setup guides for Laravel and Node, testing without real money, pricing, and what to do when payments fail.
Production · Tutorial
A step-by-step checklist for moving an x402 API from testnet to mainnet, covering wallet, network, facilitator, replay cache, alerts and the first real payment.
· 7 min read
Concepts
How AI agents pay for APIs with x402: the wallet, the EIP-3009 signature and the facilitator explained step by step, with client code and the safety limits.
· 7 min read
Laravel · Tutorial
Add x402 payments to a Laravel API with requestway/laravel-x402: install, price routes, test without a wallet and prepare for mainnet, step by step.
· 7 min read
Pricing · Analytics
Use x402 observe mode to measure what AI agents would pay per route before you charge: setup in Laravel and Node, the queries, and how to read them.
· 6 min read
Pricing · Strategy
Pricing an API for AI agents per request: how x402 prices work in atomic units, how to set fixed, tiered and dynamic prices, and how to test demand first.
· 7 min read
Testing · Tutorial
Test x402 payments on Base Sepolia for free: fake facilitators in unit tests, test USDC from the Circle faucet, a real paid call and receipt checks.
· 6 min read
Concepts
What the HTTP 402 Payment Required status code means, why it sat unused for decades, what a 402 looks like with x402 today, and how clients should handle one.
· 8 min read
Strategy · Pricing
How to decide what to charge AI agents for, which API endpoints belong behind x402, which to keep free, and how to test your choices before charging anyone.
· 7 min read
Concepts · Production
What an x402 facilitator does at each step of a payment, what it can never do with your money, and how to choose one for testnet, mainnet or self-hosting.
· 8 min read
Troubleshooting
Why x402 payments fail, stage by stage: the real error codes, what causes each one, and the concrete fix on both the client side and the server side.
· 9 min read
Strategy · Concepts
x402 vs API keys and subscriptions, compared fairly: where pay-per-request wins, where keys and plans are better, and how to run both on one Laravel API.
· 6 min read
Node.js · Tutorial
Add x402 to Express, Next.js and Hono with the official v2 packages: one shared resource server, route config, a paying client and outcome hooks.
· 7 min read
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