> ## Documentation Index
> Fetch the complete documentation index at: https://docs.nuwa.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# What is x402?

> Learn how the x402 payments protocol activates HTTP 402 for instant, web-native crypto payments.

x402 is an open, HTTP-native payment standard maintained by the Coinbase Developer Platform. It activates the long-dormant `402 Payment Required` status so any API, website, or agent can charge small crypto-denominated fees without building custom billing flows.\
The V1 specification focuses on flat-rate micropayments using the **`X-PAYMENT`** header and a standard JSON schema for negotiating payment requirements between clients, resource servers, and facilitators.

## Why x402 matters

* **Open standard, no rent seeking:** The protocol is stewarded in the open, and implementations (client, server, facilitator) can be built by anyone. [(coinbase/x402)](https://github.com/coinbase/x402)
* **HTTP-native integration:** Payments ride on ordinary HTTP requests and responses—no extra sign-in, OAuth, or signature exchanges. [(x402.org)](https://x402.org)
* **Chain & asset agnostic:** Any `(scheme, network)` pair can be registered so you can settle on Base, L2s, or other chains that meet the spec.
* **Trust-minimized settlement:** Resource servers never take custody of user funds; a facilitator verifies receipts on-chain and can optionally settle on the server’s behalf.
* **Agent-friendly micropayments:** Fees can be as low as \$0.001 with \~2 second settlement, enabling AI agents and bots to pay per-request.

## Core roles in the ecosystem

| Role                   | Responsibility                                                                                                    |
| ---------------------- | ----------------------------------------------------------------------------------------------------------------- |
| **Client**             | Requests a protected resource and composes `X-PAYMENT` payloads.                                                  |
| **Resource server**    | Exposes the API/content and responds with `402` when payment is required.                                         |
| **Facilitator server** | Optional third party that verifies and settles payments so the resource server does not need direct chain access. |

## Schemes & networks

* **Schemes** describe *how* value is moved. The first shipping scheme is `exact`, which transfers a fixed amount (e.g., “pay \$0.01 for this request”). Future schemes like `upto` add metered usage.
* **Networks** scope those schemes to a blockchain implementation (for example, `exact` on Base differs from `exact` on Solana). Clients, facilitators, and servers must explicitly agree on the `(scheme, network)` pair.

> x402 is built to be extensible: see [`specs/schemes`](https://github.com/coinbase/x402/tree/main/specs/schemes) for latest proposals, and [`ROADMAP.md`](https://github.com/coinbase/x402/blob/main/ROADMAP.md) for upcoming protocol milestones.

## Developer resources

* [x402.org — official intro and ecosystem tracker](https://x402.org)
* [coinbase/x402 — reference TypeScript implementation](https://github.com/coinbase/x402)
* [x402 PDF one-pager](https://www.x402.org/x402.pdf)
* [x402 ecosystem submissions](https://x402.org/ecosystem)

Stay up to date by watching the coinbase/x402 repository; the spec and tooling are evolving quickly as more facilitators and payment schemes come online.