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Documentation Index

Fetch the complete documentation index at: https://docs.prudra.dev/llms.txt

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

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x402 payments

x402 is an open payment protocol built on HTTP 402 status codes. When a Prudra-protected endpoint returns 402, it includes a PAYMENT-REQUIRED header containing the payment options in base64-encoded JSON. The agent decodes this header, signs an ERC-3009 authorization off-chain, and resubmits with the signature in the PAYMENT-SIGNATURE header. The agent’s wallet never sends a transaction directly. Prudra’s server receives the signed authorization, verifies it cryptographically, does the work, then settles on-chain. The agent pays with a signature — Prudra handles the blockchain interaction.

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How the challenge works

The PAYMENT-REQUIRED header contains a base64-encoded array of payment options: 
[
  {
    "scheme": "exact",
    "network": "base-mainnet",
    "maxAmountRequired": "10000",
    "resource": "https://your-api.com/analyse",
    "description": "Document analysis",
    "mimeType": "application/json",
    "payTo": "0x742d35Cc...",
    "maxTimeoutSeconds": 300,
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "extra": {
      "name": "USDC",
      "version": "2"
    }
  }
]
The agent selects an option matching its token preference (USDC), signs an ERC-3009 transferWithAuthorization off-chain, and returns it as the PAYMENT-SIGNATURE header (base64-encoded).

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Settlement flow

Settlement happens after your handler responds. The agent doesn’t wait for on-chain confirmation — Prudra handles that asynchronously. The PAYMENT-RESPONSE header in the 200 response includes the txHash and a settlementPending flag.

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When to use x402

ScenarioRecommendation
Agents using Base walletx402 or dual-protocol
Agents using USDC on Basex402 or dual-protocol
Maximum compatibilityDual-protocol (both x402 and MPP)
Session payments neededUse MPP instead
Simple, one-off paymentsx402
x402 does not support session payments. For multi-step workflows under one payment, use MPP or session payments.

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Tokens and chains

x402 currently supports:
TokenChainChain ID
USDCBase8453
USDCBase Sepolia (testnet)84532