ToolAssay

Decode EVM smart-contract transaction calldata into the function name and typed

Decode EVM smart-contract transaction calldata into the function name and typed parameters. Supply an ABI (from /api/contract-abi) or a signature like transfer(address,uint256) for a fully offline decode; with neither, the 4-byte selector is resolved via the openchain.xyz signature database (4byte.directory fallback) and each candidate signature is tried. Unknown selectors return a documented partial decode (selector + raw 32-byte words) instead of an error.

Not tested: has real-world effectsour last check, 2026-09-24
0 of 0checks answered this week
n/amedian answer time
$0.003listed price per call
n/aprice it asked us

Paid test badge: not yet. The checks above are free: we call the tool without paying and read the payment request it sends back. The Verified badge needs paid calls whose answers match the promised output, and nobody can buy a badge.

Endpoint

POST https://agent402.tools/api/calldata-decode

CategoryEverything else
Provider hostagent402.tools
Networksalgorand:wGHE2Pwdvd7S12BL5FaOP20EGYesN73ktiC1qzkkit8=, eip155:10, eip155:1329, eip155:137, eip155:143, eip155:42161, eip155:42220, eip155:43114, eip155:4663, eip155:8453, solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp, stellar:pubnet
Payment schemesexact, upto
Self-reported calls, 30 days6 from 1 payers (the provider's figure, not ours)

Our checks, last 30 days

We never call tools that send, buy, move money or file anything, not even without paying.

Example input (from the provider)

{
  "body": {
    "data": "0xa9059cbb000000000000000000000000abf4fabd7c416fb67202e5f9002389fc75e2a9d000000000000000000000000000000000000000000000000000000000000f4240"
  },
  "bodyType": "json",
  "method": "POST",
  "type": "http"
}

Promised output schema (from the provider)

{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "properties": {
    "input": {
      "additionalProperties": false,
      "properties": {
        "body": {
          "properties": {
            "abi": {
              "description": "Optional contract ABI (JSON array) - enables a fully offline decode with parameter names.",
              "type": "array"
            },
            "data": {
              "description": "0x-prefixed calldata (selector + encoded args). Max 100KB.",
              "type": "string"
            },
            "signature": {
              "description": "Optional function signature, e.g. transfer(address,uint256) - offline decode without a full ABI.",
              "type": "string"
            }
          },
          "required": [
            "data"
          ]
        },
        "bodyType": {
          "enum": [
            "json",
            "form-data",
            "text"
          ],
          "type": "string"
        },
        "method": {
          "enum": [
            "POST"
          ],
          "type": "string"
        },
        "type": {
          "const": "http",
          "type": "string"
        }
      },
      "required": [
        "type",
        "method",
        "bodyType",
        "body"
      ],
      "type": "object"
    },
    "output": {
      "properties": {
        "example": {
          "properties": {
            "decoded": {
              "type": "boolean"
            },
            "name": {
              "type": "string"
            },
            "params": {
              "items": {
                "properties": {
                  "name": {},
                  "type": {
                    "type": "string"
                  },
                  "value": {
                    "type": "string"
                  }
                },
                "type": "object"
              },
              "type": "array"
            },
            "selector": {
              "type": "string"
            },
            "signature": {
              "type": "string"
            },
            "source": {
              "type": "string"
            }
          },
          "required": [
            "selector",
            "decoded",
            "name",
            "signature",
            "params",
            "source"
          ],
          "type": "object"
        },
        "type": {
          "type": "string"
        }
      },
      "required": [
        "type"
      ],
      "type": "object"
    }
  },
  "required": [
    "input"
  ],
  "type": "object"
}

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