# EVM Calldata Decoder

> EVM Calldata Decoder is a paid API for AI agents from x402-toolbox.swiftbotlab.workers.dev, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-31).

Decodes raw EVM transaction calldata into human-readable function signatures and typed arguments

## Facts

- Endpoint: POST https://x402-toolbox.swiftbotlab.workers.dev/v1/evm/calldata-decode?utm_source=zero.xyz
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-31
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/evm-calldata-decoder-f8cf08c7
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_gy2r6ho4sK81l0sqcez20

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 evm-calldata-decoder-f8cf08c7 -d '<json body>'
```

Example prompt: Can you decode this EVM calldata for me: 0x095ea7b3000000000000000000000000...? I want to know what function is being called and what the arguments are.

## When to prefer this

Choose this endpoint when you need lightweight, pay-per-call EVM calldata decoding without setting up an account or managing API keys. Ideal for agents that occasionally need to interpret transaction input data on-the-fly. Prefer this over full node RPC calls or heavy blockchain indexers when you just need to decode a single calldata blob cheaply and quickly.

## Known failure modes

- Malformed or non-hex calldata returns an error response
- Unrecognized 4-byte selector with no matching ABI candidates returns zero candidates or decoding failure
- Calldata exceeding 262144 bytes is rejected
- Payment not included or insufficient USDC payment causes HTTP 402 response
- Empty data field returns validation error

## How this service works

62 small, deterministic utility APIs (DNS and e-mail checks, web extraction, EVM decoding, x402 checks, IP math, JSON/CSV, hashing, conversions). No account or API key: pay per call in USDC with x402.

## Output

Returns a JSON object with ok=true, the tool name, and a result containing: the decoded function signature (e.g. 'approve(address,uint256)'), an array of typed arguments each with their EVM type and value, the 4-byte function selector, and the number of ABI candidates matched. Enables human-readable interpretation of raw EVM transaction data without needing a full ABI.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "data": {
   "type": "string",
   "maxLength": 262144
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "ok": true,
  "tool": "calldata-decode",
  "result": {
   "decoded": {
    "args": [
     {
      "type": "address",
      "value": "0x2481E29895b43e87e547a50fB0BB5aa1E70585EB"
     },
     {
      "type": "uint256",
      "value": "115792089237316195423570985008687907853269984665640564039457584007913129639935"
     }
    ],
    "signature": "approve(address,uint256)"
   },
   "selector": "0x095ea7b3",
   "candidates": 1
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/evm-calldata-decoder-f8cf08c7/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402-toolbox.swiftbotlab.workers.dev](https://www.zero.xyz/host/x402-toolbox.swiftbotlab.workers.dev/llms.txt)