Decode calldata: function and arguments of an EVM call

$0.01 per call · failed calls are never charged · no account or API key needed

Decode EVM transaction calldata into the function and its arguments with viem: give the function signature (transfer(address,uint256)), or leave it out to try common ERC-20, ERC-721, ERC-1155, WETH, permit and multicall functions by selector. Numbers come back as decimal strings. Use to read what a pending or past transaction does before signing; get calldata from eth_tx. A selector that does not match is 422, uncharged.

Run it free (25 free calls) Buy credits by card (from $5) Example result (JSON)

Try it with your own inputs

0x calldata (selector plus ABI-encoded arguments), up to 8 KB

Uses one of your 25 free calls. Nothing is charged, and a call that fails is not counted.

Inputs

NameTypeDescription
data (required)string0x calldata (selector plus ABI-encoded arguments), up to 8 KB
signaturestringOptional function signature such as transfer(address,uint256)

Request

Over HTTP, with a card key from /credits:

curl -H "Authorization: Bearer adt_…" "https://agent-data-tools.revmesh2074.workers.dev/evm/decode-calldata?data=0xa9059cbb000000000000000000000000d8da6bf26964af9d7eed9e03e53415d37aa960450000000000000000000000000000000000000000000000000000000000989680"

Or one of your 25 free calls, no key:

curl "https://agent-data-tools.revmesh2074.workers.dev/evm/decode-calldata?data=0xa9059cbb000000000000000000000000d8da6bf26964af9d7eed9e03e53415d37aa960450000000000000000000000000000000000000000000000000000000000989680&trial=1"

Without a key, the same URL answers 402 Payment Required with x402 and MPP terms, so an agent with a wallet pays per call in USDC (Base, Polygon, Arbitrum or Solana over x402; Base or Tempo over MPP) and retries.

Example result

{
  "selector": "0xa9059cbb",
  "decoded": true,
  "function": "transfer(address,uint256)",
  "args": [
    {
      "type": "address",
      "value": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045"
    },
    {
      "type": "uint256",
      "value": "10000000"
    }
  ]
}

From an AI agent (MCP)

Add the MCP server to Claude, Cursor or any MCP client. This tool is evm_decode_calldata, and the first 25 successful calls are free:

https://agent-data-tools.revmesh2074.workers.dev/mcp

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