HTTP 402, Explained: The Web's Forgotten Status Code Finally Has a Job

10 October 2026 · 2 min read

paymentsx402L402MPP

The number 402 in large orange numerals on a dark background

When the web's status codes were written, one was set aside for a future nobody had built yet: 402 Payment Required. It sat unused for about thirty years. In 2026 it became the way software pays software.

The idea in one paragraph

An agent asks a server for something. The server answers 402 and says what it costs and how to pay. The agent pays and asks again, this time with proof. The server hands over the result. There is no account, no API key and no checkout page. The payment is the login.

The three protocols

L402 comes from Lightning Labs and runs on Bitcoin's Lightning Network. The server issues a Lightning invoice with an access token. In February 2026 Lightning Labs open-sourced a toolkit that lets agents run a node, pay L402 endpoints and host paid endpoints of their own.

x402 was created at Coinbase and first used stablecoins. On 2 April 2026 the Linux Foundation launched the x402 Foundation to run it as a neutral standard. Forty organizations joined at launch, with premier members including Amazon Web Services, American Express, Cloudflare, Google, Mastercard, Shopify, Stripe and Visa.

MPP, the Machine Payments Protocol, was launched by Stripe and Tempo on 18 March 2026. It uses the same 402 flow and accepts several payment methods through one protocol: stablecoins, cards via Stripe and Visa, and Bitcoin over Lightning.

The news that matters: they are converging

For most of the year this looked like a format war. It looks less like one now.

MPP accepts Lightning and cards side by side.
In late September, Block joined the x402 Foundation and added Lightning support to x402.
Visa's Intelligent Commerce Connect, announced in April, lists support for several agent protocols behind one integration.

The practical reading: pick a marketplace or gateway that speaks more than one, and stop worrying about which wins.

How big is this, really?

Small, and growing. One industry newsletter estimated in mid-2026 that x402 had about 69,000 active agents and $50 million in total volume. Treat that as an estimate, not an audited figure. An analyst at Forrester argued in March that agent payments could finally make micropayments work, because software does not mind paying a tenth of a cent a thousand times.

What to do with this

Running agents: give them a wallet with a hard cap and let them pay per call.
Selling a tool or dataset: a 402 endpoint lets you charge without building billing.

Noden accepts Lightning and card-funded credits, and only charges when the result passes its check. See how it works.