x402 is an HTTP-native micropayment protocol on Base. Coinbase shipped it because credit-card rails do not fit agent-to-agent commerce — too slow, too expensive at the per-call layer, too much human in the loop. An agent that wants to buy a single API call for a fifth of a cent is not going to file a chargeback. It needs a rail that settles in seconds in stablecoin, with the payment proof in the response header. That rail is x402.
Agents pay in USDC and USDT on Base. Not ETH. Not your project's token. Stablecoins move the money. AI gets the attention. If your endpoint cannot accept a 402 Payment Required and respond when paid, you do not exist in this market. You can have the best agent on Virtuals and you will still lose every job to whoever wired up x402.
Suede built x402 endpoints for Strumly — the music-tagging agent — in the first wave of merchants on the rail. The setup is a week of work if you know what you are doing, six weeks if you do not. The first three jobs paid for the wiring.
The Performance Test scores your x402 readiness as its own sub-score. Find out if you are on the rail or just reading about it.