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Saylor Innovations EVM Selector / Topic Decoder
x402
Saylor Innovations EVM Selector / Topic Decoder is a paid API for AI agents from saylorinnovations.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-18).
Decodes a 4-byte EVM function selector or 32-byte event topic into candidate human-readable signatures, with verification status and collision warnings
Price / call$0.01
Success—
StatusUnknown
How this service works
Decode a 4-byte EVM function selector or 32-byte event topic into candidate signatures from OpenChain and 4byte with the verified one first and collision warnings
Output
Returns the input hex selector or topic, its kind (function or event), a best_guess human-readable signature, an array of candidate signatures with their sources (OpenChain and/or 4byte) and whether a verified contract has been seen using each, plus an optional collision_warning if multiple signatures share the selector, and a well_known_meaning field for widely-recognized selectors.
Example use cases
Identify unknown contract method call
“I'm reading a raw Ethereum transaction and the input data starts with 0xa9059cbb — can you decode that 4-byte selector and tell me what function it is?”
Debug smart contract event topic
“I've got this 32-byte event topic from an Ethereum log: 0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef — what event does it represent and is it from a verified contract?”
Audit ABI collision risk
“Can you check the EVM selector 0x23b872dd and tell me if there are multiple function signatures that map to it? I need to know if there's a collision warning before I trust it in my security audit.”
Technical details
Endpoint
GEThttps://saylorinnovations.com/api/evm/selector?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need to decode an EVM function selector or event topic into its human-readable Solidity signature, especially when you want verification status (confirmed seen in a verified contract) and collision detection. It aggregates both OpenChain and 4byte.directory sources, making it more reliable than querying either alone. Prefer it over manual ABI lookups when building blockchain explorers, transaction analyzers, security auditing tools, or smart contract debugging pipelines.
Side effects
- Unknown selector not found in either OpenChain or 4byte databases — returns empty candidates array
- Invalid hex format (wrong length or non-hex characters) — request rejected
- Selector with multiple conflicting signatures triggers collision warning but still returns results
- External database (OpenChain or 4byte) temporarily unavailable — partial or error response
- Rate limiting or payment failure for the $0.01 USDC x402 fee
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Tags
x402
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