Guide · Story · 2026

HTTP 402: thirty years dormant, now the agent payment layer

The web always had a status code for “Payment Required.” For most of its life, almost nobody used it for real. Then machines started buying API calls by themselves — and 402 finally had a job.

What 402 always meant

In the HTTP status registry, 402 Payment Required sat reserved for future digital payment schemes. Browsers did not standardize a checkout UI around it. Sites invented accounts, cookies, and API keys instead.

Why it woke up

• Stablecoins made “one cent” a real unit without card fees eating it.
• Fast chains made settlement feel like normal web latency.
• Agents needed programmatic pay-per-request without a human on a billing page.

Coinbase launched the x402 protocol in 2025 to define what a 402 response should contain and how clients retry with proof. In 2026 governance sits with the x402 Foundation under the Linux Foundation, with a broad industry membership.

What changed with the protocol (not just the code)

Status 402 alone is not enough. x402 adds the machine contract: accepted networks (CAIP-2), amounts, schemes, optional facilitators, and headers for requirements and signatures. V2 cleaned that envelope further for multi-chain and modern clients.

Why builders should care

You can still sell subscriptions. You can still use Stripe. x402 is for the long tail of tiny, bursty, agent-shaped demand — the calls that never justified a sales call or a monthly plan.

Try the modern 402

On this site the lab returns a real 402 with a v2-shaped body. The donate endpoint does the same with on-chain verification. That is the status code earning its keep.

Ship x402 is an independent educational project. Not affiliated with the x402 Foundation, Coinbase, or the Solana Foundation. Not financial advice.