# Lumen EVM Calldata Decoder

> Lumen EVM Calldata Decoder is a paid API for AI agents from lumenworks-x402-decoder.onrender.com, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-11).

Decodes raw EVM calldata into function selector, matching signatures from built-in and openchain/4byte databases, and ABI-decoded arguments for each candidate signature

## Facts

- Endpoint: POST https://lumenworks-x402-decoder.onrender.com/v1/calldata/decode?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-11
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/lumen-evm-calldata-decoder-0d270902
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_0BzuIlTZ2iwRILA41G-xu

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 lumen-evm-calldata-decoder-0d270902 -d '<json body>'
```

Example prompt: Can you decode this raw EVM calldata for me — 0xa9059cbb000000000000000000000000ee9790cb3960952f585379f831a89b4e00b4029a00000000000000000000000000000000000000000000000000000000000f4240 — and tell me what function it calls and what the decoded arguments are?

## When to prefer this

Use this endpoint when you have raw hex calldata from an EVM transaction and need to identify the function being called and decode its arguments without having the ABI on hand. Ideal for security review, transaction auditing, mempool analysis, or debugging failed calls. Prefer this over manual ABI lookups when the contract ABI is unavailable and the selector needs to be resolved from public signature databases.

## Known failure modes

- Unknown selector: calldata selector not found in built-in or openchain/4byte databases — returns selector with empty candidates
- Malformed calldata: non-hex or truncated input causes a parse error response
- Ambiguous signatures: multiple candidates returned when selector maps to more than one signature — agent must choose
- Network timeout: openchain/4byte external lookup fails, may return partial results from built-in database only

## How this service works

Use when you hold raw EVM calldata and need to know what function it calls: returns selector, matching signatures (built-in + openchain/4byte) and ABI-decoded args for each candidate; unknown selecto…

## Output

Returns the 4-byte function selector, the number of matching signatures found, the best-match source (built-in or openchain/4byte), the matched function signature string (e.g. 'transfer(address,uint256)'), and an array of candidate signatures each with their ABI-decoded argument values

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "source": "openchain/4byte",
  "decoded": {
   "args": [
    "0xee9790cB3960952F585379F831a89b4e00B4029A",
    "1000000"
   ],
   "signature": "transfer(address,uint256)"
  },
  "selector": "0xa9059cbb",
  "candidates": [
   {
    "args": [
     "0xee9790cB3960952F585379F831a89b4e00B4029A",
     "1000000"
    ],
    "signature": "transfer(address,uint256)"
   }
  ],
  "signaturesFound": 1
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/lumen-evm-calldata-decoder-0d270902/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from lumenworks-x402-decoder.onrender.com](https://www.zero.xyz/host/lumenworks-x402-decoder.onrender.com/llms.txt)