# EVM Calldata Decoder

> EVM Calldata Decoder is a paid API for AI agents from golf-evm-math.x402-evm-math.workers.dev, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-30).

Decodes EVM calldata hex strings into human-readable function signatures and typed arguments using a built-in table of ~60 common ERC20/721/1155, Uniswap, and Aave signatures, or a user-supplied signature.

## Facts

- Endpoint: GET https://golf-evm-math.x402-evm-math.workers.dev/evm/decode?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-30
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/evm-calldata-decoder-aff7cb83
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_PIe2_5y4iPUc9VVHVUvXp

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-aff7cb83
```

Example prompt: Can you decode this EVM calldata for me: 0xa9059cbb000000000000000000000000ab5801a7d398351b8be11c439e05c5b3259aec9000000000000000000000000000000000000000000000000016345785d8a0000 — I want to know what function was called and what the arguments are.

## When to prefer this

Choose this endpoint when you need to quickly decode EVM transaction calldata without setting up a full ABI decoder or node connection, especially for common DeFi protocols (ERC20, ERC721, ERC1155, Uniswap, Aave). Ideal for transaction analysis pipelines, on-chain monitoring, and debugging tools. Supports custom signatures for non-standard contracts.

## Known failure modes

- Unknown selector not in built-in table and no custom signature supplied — returns known:false with no decoded args
- Malformed or non-hex calldata input — returns error response
- Calldata too short to contain a valid 4-byte selector — parse error
- Supplied custom signature does not match the calldata selector — decoding mismatch
- Network or payment authorization failure returns 402 Payment Required

## How this service works

Exact EVM address, calldata, Uniswap V2/V3 and impermanent-loss math. Pay per call in USDC on Base via x402.

## Output

Returns a JSON object indicating whether the function selector is known, the 4-byte selector (e.g. 0xa9059cbb), the resolved function signature name and parameter types, and the decoded typed argument values extracted from the calldata.

## 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",
     "properties": {}
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "known": true,
  "selector": "0xa9059cbb"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/evm-calldata-decoder-aff7cb83/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from golf-evm-math.x402-evm-math.workers.dev](https://www.zero.xyz/host/golf-evm-math.x402-evm-math.workers.dev/llms.txt)