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Documentation Index

Fetch the complete documentation index at: https://docs.x402.org/llms.txt

Use this file to discover all available pages before exploring further.

Payment schemes define the payment semantics for a resource: exact is for fixed-price requests where the buyer authorizes the advertised amount, upto is for single-request usage-based billing where the buyer authorizes a maximum and the seller charges actual usage, and batch-settlement is for high-volume or repeated micropayments where per-request authorizations are accumulated against a reusable channel. Network implementations define how those semantics are encoded for EVM, SVM, TVM (TON), AVM, Stellar, Aptos, Hedera, and other networks; see SDK Features for current SDK support.

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Schemes in a 402 Response

A protected resource advertises one or more payment requirements in its HTTP 402 Payment Required response. The scheme names the payment semantics and network names the network implementation. 
{
  "x402Version": 2,
  "error": "PAYMENT-SIGNATURE header is required",
  "resource": {
    "url": "https://api.example.com/weather",
    "description": "Weather data",
    "mimeType": "application/json"
  },
  "accepts": [
    {
      "scheme": "exact",
      "network": "eip155:84532",
      "amount": "1000",
      "asset": "0x036CbD53842c5426634e7929541eC2318f3dCF7e",
      "payTo": "0xYourEvmAddress",
      "maxTimeoutSeconds": 60,
      "extra": {
        "name": "USDC",
        "version": "2"
      }
    },
    {
      "scheme": "exact",
      "network": "solana:EtWTRABZaYq6iMfeYKouRu166VU2xqa1",
      "amount": "1000",
      "asset": "So11111111111111111111111111111111111111112",
      "payTo": "YourSolanaAddress",
      "maxTimeoutSeconds": 60,
      "extra": {
        "feePayer": "EwWqGE4ZFKLofuestmU4LDdK7XM1N4ALgdZccwYugwGd"
      }
    }
  ]
}
Servers register scheme implementations for the networks they advertise. Clients register scheme implementations for the networks they can pay on. When the client receives a 402 response, the SDK selects an accepts entry whose scheme and network match a registered implementation.

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Specs

For scheme-level payload semantics, see the network-agnostic specifications. Each scheme page links to its currently implemented network specs.