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ABI Selector Map Generator
x402
ABI Selector Map Generator is a paid API for AI agents from x402-audit.tatschluizguilherme.workers.dev, paid per call via x402, $0.1/call, status unknown (last checked 2026-09-15).
Generates a complete selector map from a contract ABI — 4-byte selectors for functions/errors and 32-byte topic0 for events — entirely offline with no RPC or API key required
Price / call$0.1
Success—
StatusUnknown
How this service works
Pay-per-call on-chain API for AI agents and developers: wallet audits, token safety audits (honeypot detection), live gas prices, token prices, transaction receipts, balances, ENS resolution, block data, ERC-20 allowances, transaction simulation, swap quotes and multicall batches — all computed on-chain via public RPCs (no external market API). Pay per request in USDC on Base via the x402 exact scheme (EIP-3009 transferWithAuthorization). No API key, no signup, no subscription.
Output
Returns a complete selector map object containing: for each function — the 4-byte hex selector, canonical signature string, and typed input/output parameter list; for each event — the 32-byte hex topic0, canonical signature, indexed/anonymous flags per parameter; for each error — the 4-byte hex selector and canonical signature. Also includes a verification object (verify.known) indicating which entries the API's decode dictionary can already decode or encode.
Example use cases
Smart contract calldata routing table
“I have the ABI for a Uniswap V3 pool contract — can you generate a complete selector map so I know the 4-byte selector and canonical signature for every function and the topic0 for every event it emits?”
Offline event signature fingerprinting
“Here's the ABI JSON for our NFT contract. I need the 32-byte topic0 hashes for all its events, along with which parameters are indexed and which are anonymous, computed without hitting any RPC endpoint.”
ABI decode coverage verification
“Given this DeFi protocol ABI, generate the full selector map and tell me which functions and events your decode dictionary already knows how to decode — I want to see the verify.known round-trip results for everything in the ABI.”
Technical details
Endpoint
GEThttps://x402-audit.tatschluizguilherme.workers.dev/abiWhen to prefer
Choose this endpoint when you need to compute EVM function selectors, event topic0 hashes, or error selectors from a contract ABI entirely offline — no blockchain node, no Etherscan API key, no network latency. Ideal for tooling pipelines, calldata routers, event decoders, or any workflow that needs a complete selector dictionary from an ABI JSON instantly. Prefer over RPC-based approaches when chain-agnosticism and determinism matter, or when you want to verify decode coverage against a known selector dictionary.
Side effects
- Malformed or invalid ABI JSON returns a parse error
- ABI entries missing required fields (type, name, inputs) cause incomplete selector generation
- Empty ABI array returns an empty selector map with no entries
- Non-standard or experimental ABI entry types may be skipped or flagged
- Oversized ABI payloads may hit Cloudflare Worker request size limits
- Payment failure (x402) blocks request before processing
Output
Schema · Response
{
"type": "json",
"example": {
"count": {
"other": 0,
"errors": 0,
"events": 1,
"functions": 1
},
"other": [],
"errors": [],
"events": [
{
"name": "Transfer",
"inputs": [
{
"name": "from",
"type": "address",
"indexed": true
},
{
"name": "to",
"type": "address",
"indexed": true
},
{
"name": "value",
"type": "uint256",
"indexed": false
}
],
"topic0": "0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef",
"verify": {
"name": "Transfer",
"known": true
},
"anonymous": false,
"signature": "Transfer(address,address,uint256)"
}
],
"network": "offline",
"functions": [
{
"name": "transfer",
"inputs": [
{
"name": "to",
"type": "address"
},
{
"name": "value",
"type": "uint256"
}
],
"verify": {
"args": [
"address",
"uint256"
],
"name": "transfer",
"known": true
},
"outputs": [],
"selector": "0xa9059cbb",
"signature": "transfer(address,uint256)",
"stateMutability": "nonpayable"
}
],
"requestedAt": "2026-08-05T10:00:00.000Z"
}
}Tags
x402
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