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ChainRead Block Lookup
x402
ChainRead Block Lookup is a paid API for AI agents from api.firstmention.uk, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-29).
Fetches on-chain block data for a specified block number or 'latest' on Base or Ethereum, paid per-call via x402 USDC micropayment.
Price / call$0.01
Success—
StatusUnknown
How this service works
Pay-per-call HTTP APIs, paid with x402 in USDC on Base (eip155:8453): agentkit, api-change-check, basedue, basewatch, chainread, check-sanctions, chgwatch, company-facts, composite, edgar, feednews, pageaudit, solcheck, token-dd, txpreflight, walletcheck, webmd, webread, websearch, x402index. Each operation describes its service.
Output
Returns a JSON object with the block data including chain identifier, risk/score fields if applicable, flags, verdict, and metadata about the payer address and price paid in USD.
Example use cases
Audit recent Base block
“Pull up the latest block on Base so I can see what just got confirmed on-chain.”
Verify specific Ethereum block
“Look up block 18500000 on Ethereum and tell me the details.”
Monitor block finality
“Fetch block number 5000000 on Base — I want to confirm it's been finalized and see the block data.”
Technical details
Endpoint
POSThttps://api.firstmention.uk/s/chainread/block?utm_source=zero.xyzWhen to prefer
Use this endpoint when an AI agent needs to retrieve on-chain block details from Base or Ethereum and can pay $0.01 USDC per call via the x402 micropayment protocol — ideal for agents that need trustless, pay-per-use access without API key management.
Side effects
- Invalid block number format returns an error
- Block number not yet mined returns not-found error
- Unsupported chain value (not 'base' or 'ethereum') returns validation error
- Payment failure via x402 results in 402 response requiring USDC payment on Base
- Network timeout if the RPC node is slow
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| hash | string | 0x transaction hash (for /tx) |
| chain | string | |
| number | string | Block number or 'latest' (for /block) |
| address | string | 0x address or ERC-20 contract address |
| addresses | array | Up to 25 addresses (for /batch) |
Output
Schema · Response
{
"type": "json",
"example": {
"risk": "medium",
"_meta": {
"payer": "0x...",
"price_usd": 0.01
},
"chain": "base",
"flags": [
{
"code": "owner_holds_power",
"severity": "high"
}
],
"score": 45,
"address": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
"verdict": "CAUTION"
}
}Tags
x402
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