Glossary
HTTP 402
HTTP 402 is defined here as follows. HTTP status code 402, Payment Required. RFC 9110 reserves the code for future use. x402, L402, and the Machine Payments Protocol use a 402 response as the signal that the request needs payment. The directory source for this term is RFC 9110, status 402 Payment Required.
Last verified 2026-10-17
Sources
Listings
Directory listings whose sources describe this mechanism.
| Name | Status | Category | Open source | Mechanism |
|---|---|---|---|---|
| L402 | Live | Payment rails | Yes | HTTP 402 flow that pairs a macaroon with a Lightning invoice. The client pays, then presents the preimage so the server can check payment without a lookup. http-402, lightning, macaroons |
| Machine Payments Protocol | Live | Payment rails | Yes | Open HTTP 402 protocol, co-authored by Stripe and Tempo, so an agent can authorize payment for an API with a card or a stablecoin and receive a receipt. http-402, cards, stablecoins |
| MetaMask Agent Wallet | Live | Payment rails | No | Agent wallet CLI for sending tokens and paying x402 requests. Guard Mode can enforce address and recipient allowlists and a rolling 24 hour outflow limit, and it asks for 2FA outside that policy. wallets, spend-limits, http-402 |
| Nevermined | Live | Payment rails | No | Payments facilitator that verifies and settles x402 and MPP charges against a payment plan, with metering and delegated card spending. http-402, metering, cards |
| Polygon Agent CLI | Live | Payment rails | Yes | Agent CLI with an embedded smart wallet. Session mode spends only inside an allowance the owner approves, x402 payments can be capped per call, and session logout revokes that install. wallets, spend-limits, http-402 |
| Stripe link-cli | Live | Payment rails | Yes | CLI for an agent to request a card purchase or a Machine Payments Protocol charge. Link asks the customer to approve the spend request, then returns a one time payment credential. cards, spend-limits, http-402 |
| Sui Agentic Payments | Beta | Payment rails | No | Testnet gateway where an agent pays per API call in USDC on Sui. The owner sets an onchain grant with allowed services, a total budget, a per payment cap, and an expiry, and can revoke it. http-402, spend-limits, stablecoins |
| Tempo Wallet | Live | Payment rails | No | Wallet and CLI that let an agent discover paid services, preview MPP terms, and pay under a max spend cap. wallets, http-402, spend-limits |
| x402 | Live | Payment rails | Yes | Open HTTP payment standard. A server answers with status 402, the client pays and retries, and a facilitator can verify and settle the payment. http-402, stablecoins, pay-per-call |
Questions
- What is HTTP 402?
- HTTP status code 402, Payment Required. RFC 9110 reserves the code for future use. x402, L402, and the Machine Payments Protocol use a 402 response as the signal that the request needs payment.
- Which listings use HTTP 402?
- L402, Machine Payments Protocol, MetaMask Agent Wallet, Nevermined, Polygon Agent CLI, Stripe link-cli, Sui Agentic Payments, Tempo Wallet, x402.
- When was HTTP 402 last verified?
- Last verified 2026-10-17.