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Vextorium EVM/Solana Function Selector Decoder
x402
Vextorium EVM/Solana Function Selector Decoder is a paid API for AI agents from api.vextorium.com, paid per call via x402, $0.003/call, status unknown (last checked 2026-10-15).
Decodes an EVM function selector (4 bytes) or event topic hash (32 bytes) into human-readable Solana/EVM ABI signatures using the 4byte.directory database
Price / call$0.003
Success—
StatusUnknown
How this service works
558 pay-per-call data APIs for AI agents: Solana and EVM on-chain data, tokenized stocks, DeFi, Hyperliquid, economy and official statistics, FX, validation, web and developer tools. Pay in USDC via x402.
Output
Returns the decoded function or event signature(s) matching the provided selector or topic hash, including the hex code, type (function or event), source database (4byte.directory), number of possible colliding signatures, and a note about collisions. The oldest/most common match is typically the canonical one.
Example use cases
Identify unknown calldata method
“I'm analyzing a raw Ethereum transaction and the calldata starts with 0xa9059cbb — what smart contract function is that calling?”
Decode DeFi event topic hash
“Can you tell me what EVM event this topic hash 0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef corresponds to?”
Audit smart contract interaction
“I'm auditing on-chain activity and found a transaction with selector 0x23b872dd — decode that selector and tell me how many known signatures match it.”
Technical details
Endpoint
POSThttps://api.vextorium.com/v1/decode-selector?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need to reverse-engineer an EVM function selector (4 bytes, 0x + 8 hex) or event topic hash (32 bytes, 0x + 64 hex) into a human-readable ABI signature. Ideal for transaction analysis, calldata decoding, smart contract auditing, and DeFi debugging. Prefer this over manual 4byte.directory lookups when automating on-chain data pipelines.
Side effects
- Selector not found in 4byte.directory — returns empty signatures array
- Invalid hex format (missing 0x prefix or wrong byte length) — validation error
- Selector has multiple collisions — returns all candidates with a note that the oldest is usually correct
- Network timeout to upstream 4byte.directory — may return error
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| signature | string | Function selector (0x + 8 hex) or event topic (0x + 64 hex) |
Output
Schema · Response
{
"type": "json",
"example": {
"code": "0xa9059cbb",
"note": "The same code can match several signatures (collisions); the oldest is usually the real one. Source: 4byte.directory.",
"type": "funcion",
"source": "4byte.directory",
"possible": 6,
"signatures": [
"transfer(address,uint256)",
"many_msg_babbage(bytes1)"
]
}
}Tags
x402
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