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Plainchain x402 Echo
x402
Plainchain x402 Echo is a paid API for AI agents from plainchain.appin60.com, paid per call via x402, $0.001042/call, status unknown (last checked 2026-10-14).
Echoes back a verified x402 payment receipt, confirming that a micropayment was correctly received, parsed, and validated before granting access to Plainchain's blockchain data APIs.
Price / call$0.001042
Success—
StatusUnknown
How this service works
Gas, balances, token data, address type, approvals, transaction decoding, x402 receipt verification and verifiable randomness on Base, Arbitrum, Ethereum and Optimism. No API key: pay $0.001-$0.01 per call in USDC on Base via x402.
Output
Returns a JSON object containing: the payer's wallet address, the payment scheme (e.g. 'exact'), the network identifier (e.g. 'eip155:8453' for Base), x402 protocol version, the authorized amount in micro-USDC, the list of echoed extensions (e.g. ['bazaar']), and header check results including whether the bazaar extension was echoed and the expected header name.
Example use cases
Debugging x402 integration before production
“I'm building an agent that pays for Plainchain API calls using x402 on Base — can you hit the echo endpoint with my current payment header and show me what payer address and scheme the server parsed out, so I know everything is wired up correctly?”
Confirming bazaar extension is recognized
“I'm routing my Plainchain payments through Bazaar and I need to confirm the bazaar extension is being echoed back properly in the payment receipt — can you verify that my x402 v2 payment header includes the bazaar extension and it's acknowledged?”
Validating USDC authorization amount
“Before I start making a batch of chain data queries on Plainchain, can you check the echo endpoint to confirm my payment authorization amount shows 1042 microUSDC and the network is eip155:8453 Base?”
Technical details
Endpoint
GEThttps://plainchain.appin60.com/v1/x402/echo?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need to validate that your x402 micropayment integration is correctly configured before calling Plainchain's substantive blockchain data endpoints. It is the right choice for debugging payment flows, confirming payer address extraction, verifying extension handling (e.g. bazaar), or testing that USDC authorization amounts are parsed correctly on Base — all without consuming a higher-cost data query.
Side effects
- Missing or malformed PAYMENT-SIGNATURE header returns a 402 Payment Required response
- Insufficient payment amount causes authorization failure
- Wrong network specified in payment header causes rejection
- Invalid x402 version in header may not be parsed
- Expired payment authorization window causes failure
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| required | string | |
| properties | string |
Output
Schema · Response
{
"type": "json",
"example": {
"payer": "0x...",
"advice": [],
"checks": {
"headerName": "PAYMENT-SIGNATURE (v2)",
"bazaarExtensionEchoed": true
},
"scheme": "exact",
"network": "eip155:8453",
"x402Version": 2,
"amountAuthorized": "1042",
"extensionsEchoed": [
"bazaar"
]
}
}Tags
x402
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