# Web3 Tools – EVM Calldata Splitter

> Web3 Tools – EVM Calldata Splitter is a paid API for AI agents from web3-tools.x402tookit.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-21).

Splits raw EVM calldata into its 4-byte function selector and 32-byte argument words, identifies known ERC-20/ERC-721 function signatures, and flags embedded Ethereum addresses.

## Facts

- Endpoint: GET https://web3-tools.x402tookit.com/calldata-split?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-21
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/web3-tools-evm-calldata-splitter-03b4a1e9
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_uiW73jCUa8SYlfAwOB9DC

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability web3-tools-evm-calldata-splitter-03b4a1e9
```

Example prompt: Can you split this EVM calldata for me and tell me what function it's calling and whether any of the arguments look like Ethereum addresses? The calldata is 0xa9059cbb000000000000000000000000d8da6bf26964af9d7eed9e03e53415d37aa960450000000000000000000000000000000000000000000000000de0b6b3a7640000

## When to prefer this

Use this endpoint when you need to programmatically decode raw EVM transaction input data without a full ABI — especially when you want automatic identification of common ERC-20/ERC-721 calls, embedded address detection, and unlimited-approval flagging in a single lightweight call. Prefer it over a full ABI decoder when you don't have the ABI or just need quick structural insight into what a transaction is doing.

## Known failure modes

- Invalid or non-hex input returns an error
- Calldata shorter than 4 bytes cannot yield a selector
- Unknown selectors return null for knownSignature
- Truncated word list when calldata is very long (wordsTruncated: true)
- Missing required 'data' query parameter returns a validation error

## How this service works

Split EVM calldata into its 4-byte selector and 32-byte words, naming common ERC-20/721 calls and spotting addresses.

## Output

Returns the 4-byte function selector, a human-readable known signature if recognized (e.g. 'transfer(address,uint256)' for ERC-20), an array of 32-byte argument words each annotated with its index, hex value, decoded uint256, and whether it looks like an Ethereum address, plus total byte counts, trailing byte count, an unlimited-approval flag, a summary verdict, and any applicable disclaimers.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "data"
     ],
     "properties": {
      "data": {
       "type": "string",
       "description": "Calldata hex, with or without 0x"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "asOf": {
       "type": [
        "null",
        "string"
       ]
      },
      "words": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "object",
        "properties": {
         "hex": {
          "type": [
           "null",
           "string"
          ]
         },
         "index": {
          "type": [
           "null",
           "number"
          ]
         },
         "address": {
          "type": [
           "null",
           "string"
          ]
         },
         "asUint256": {
          "type": [
           "null",
           "string"
          ]
         },
         "isMaxUint256": {
          "type": [
           "boolean",
           "null"
          ]
         },
         "looksLikeAddress": {
          "type": [
           "boolean",
           "null"
          ]
         }
        }
       }
      },
      "source": {
       "type": [
        "null",
        "string"
       ]
      },
      "reasons": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "string"
       }
      },
      "summary": {
       "type": [
        "null",
        "string"
       ]
      },
      "verdict": {
       "type": [
        "null",
        "string"
       ]
      },
      "degraded": {
       "type": [
        "boolean",
        "null"
       ]
      },
      "selector": {
       "type": [
        "null",
        "string"
       ]
      },
      "wordCount": {
       "type": [
        "null",
        "number"
       ]
      },
      "disclaimer": {
       "type": [
        "null",
        "string"
       ]
      },
      "notCheck
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/web3-tools-evm-calldata-splitter-03b4a1e9/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from web3-tools.x402tookit.com](https://www.zero.xyz/host/web3-tools.x402tookit.com/llms.txt)