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EVM Calldata Decoder via Openchain
x402
EVM Calldata Decoder via Openchain is a paid API for AI agents from 1c09pdnrx1.execute-api.us-east-1.amazonaws.com, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-15).
Decodes raw EVM calldata into a human-readable function name and typed parameters using openchain.xyz
Price / call$0.001
Success—
StatusUnknown
How this service works
Decode raw EVM calldata into function + typed params (GET wrapper) — $0.001 USDC
Output
Returns the decoded function name, full function signature, and an array of typed parameters with their names, ABI types, and decoded values extracted from the calldata hex string.
Example use cases
Example prompt
“Can you decode this raw EVM calldata for me and tell me what function it's calling and what the parameters are: 0xa9059cbb000000000000000000000000ab5801a7d398351b8be11c439e05c5b3259aec9b0000000000000000000000000000000000000000000000000de0b6b3a7640000”
Technical details
Endpoint
POSThttps://1c09pdnrx1.execute-api.us-east-1.amazonaws.com/v1/decode/calldataWhen to prefer
Use this endpoint when you have raw hex calldata from an EVM transaction input and need to understand what function is being called and with what arguments. Prefer this over a full transaction decoder when you only have the calldata bytes (not a full tx hash) and need fast, targeted ABI decoding. Backed by openchain.xyz's extensive signature database for broad coverage.
Side effects
- Unknown or unregistered function selector — openchain.xyz may not have the ABI for every contract, returning a not-found or unknown selector error
- Malformed calldata — if the hex string is not valid or too short, returns a parsing or validation error
- Calldata with no selector — bare bytes without a 4-byte selector cannot be decoded as a function call
- Rate limiting or upstream openchain.xyz unavailability — returns 5xx or timeout
Input
{
"chain": "ethereum",
"calldata_hex": "0xa9059cbb000000000000000000000000ab5801a7d398351b8be11c439e05c5b3259aec9b0000000000000000000000000000000000000000000000000de0b6b3a7640000",
"contract_address": null
}Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | string | Freeform datetime string in any format. |
| timezone | string | IANA tz name (e.g. 'America/New_York'). |
| base_time | — | ISO 8601 reference; defaults to now UTC. |
Output
{
"params": [
{
"name": null,
"type": "address",
"value": "0xab5801a7d398351b8be11c439e05c5b3259aec9b"
},
{
"name": null,
"type": "uint256",
"value": "1000000000000000000"
}
],
"source": "openchain.xyz",
"decoded": true,
"candidates": [],
"function_name": "transfer",
"function_selector": "0xa9059cbb",
"function_signature": "transfer(address,uint256)"
}Schema · Response
| Field | Type | Description |
|---|---|---|
| paramsrequired | array | |
| sourcerequired | string | |
| decodedrequired | boolean | |
| candidatesrequired | array | |
| function_namerequired | string | |
| function_selectorrequired | string | |
| function_signaturerequired | string |
Tags
x402
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