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OpenVerbs Chain EVM Calldata Decoder
x402
OpenVerbs Chain EVM Calldata Decoder is a paid API for AI agents from chain.openverbs.com, paid per call via x402, $0.004/call, status unknown (last checked 2026-10-29).
Decodes a 4-byte function selector or full EVM calldata into a human-readable function signature and decoded argument values, using a supplied ABI or public signature registries as fallback.
Price / call$0.004
Success—
StatusUnknown
Output
Returns the resolved human-readable function signature (e.g. 'transfer(address,uint256)'), the function name, parameter types, and — when full calldata is provided — the decoded argument values mapped to their parameter names and types. If no ABI is supplied, the selector is looked up in public signature registries with automatic fallback.
Example use cases
Identify unknown transaction function call
“I'm looking at a pending Ethereum transaction and the input data starts with 0x23b872dd — can you tell me what function that 4-byte selector corresponds to?”
Decode token transfer calldata
“Decode this full calldata for me and tell me what function is being called and with what arguments: 0xa9059cbb000000000000000000000000d8dA6BF26964aF9D7eEd9e03E53415D37aA96045000000000000000000000000000000000000000000000000002386f26fc10000”
Verify calldata against known ABI
“I have this calldata 0x23b872dd and the ABI signature 'function transferFrom(address,address,uint256)' — can you decode the calldata against that ABI and confirm the argument values?”
Technical details
Endpoint
POSThttps://chain.openverbs.com/v1/decode?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need to interpret raw EVM transaction input data — either for debugging, auditing, or displaying human-readable transaction details. Prefer this over manual ABI lookups when you don't have an ABI handy and want automatic registry fallback, or when you have an ABI and want deterministic offline decoding. Ideal for blockchain explorers, transaction monitoring agents, smart contract auditing tools, and wallet UIs that need to label transaction actions.
Side effects
- Unknown selector not found in any public registry returns an error or empty result
- Malformed calldata hex (odd length, non-hex characters) returns a validation error
- ABI mismatch: provided ABI signatures don't match the selector, causing decode failure
- Calldata too short (missing arguments) causes argument decoding to fail
- Network or registry lookup timeout if public registry is unavailable
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| abi | — | Optional human-readable signatures, e.g. ["function transfer(address,uint256)"], for an exact offline decode. |
| data | string | Full calldata hex (selector + arguments). |
| selector | string | 4-byte function selector, e.g. 0xa9059cbb. |
Tags
x402
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