# EVM Calldata & Transaction Decoder

> EVM Calldata & Transaction Decoder is a paid API for AI agents from api.x402node.dev, paid per call via x402, $0.05/call, status unknown (last checked 2026-09-14).

Decodes EVM calldata or a Base transaction hash into a human-readable function call, including the function signature, 4-byte selector, and typed decoded arguments.

## Facts

- Endpoint: GET https://api.x402node.dev/chain/tx-decode
- Price: $0.05/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/api-x402node-dev-ecf3e94c
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_9HzIY8nnaAGDoVrKt8B7Q

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 api-x402node-dev-ecf3e94c
```

Example prompt: Can you decode this Base transaction hash 0x3f7a...b29c and tell me what function was called, the 4-byte selector, and what the typed arguments were?

## When to prefer this

Use this endpoint when you need to interpret raw EVM calldata or a Base chain transaction hash without manually providing an ABI — it resolves function signatures via selector databases and decodes typed arguments automatically. Prefer it over manual ABI decoding when the ABI is unknown or when you need a quick, human-readable breakdown of a contract interaction.

## Known failure modes

- Unknown function selector not found in 4byte.directory or embedded ABI — returns unresolvable selector error
- Invalid or malformed calldata hex — returns parse error
- Transaction hash not found on Base — returns not found error
- Calldata too short to contain a valid selector — returns invalid input error
- Network timeout fetching transaction from Base RPC — returns timeout error

## How this service works

Decode EVM calldata or a Base tx hash into a readable function call: signature, selector, and decoded typed arguments. Search terms: calldata decoder, ABI decode, function selector 4byte, transaction decoder, EVM tx decode. Accepts payment on Base or Solana — either network works.

## Output

Returns the decoded function signature (e.g. transfer(address,uint256)), the 4-byte selector, and all decoded typed arguments with their names, types, and values — making raw calldata or a tx hash fully human-readable.

## Example request

```json
{
 "data": "0xa9059cbb000000000000000000000000742d35cc6634c0532925a3b844bc9e7595f42bd20000000000000000000000000000000000000000000000000000000000000001"
}
```

## 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",
      "tx"
     ],
     "properties": {
      "to": {
       "type": "string",
       "description": "Target format (optional)"
      },
      "tx": {
       "type": "string",
       "description": "Tx (required)"
      },
      "data": {
       "type": "string",
       "description": "Data (required)"
      },
      "txhash": {
       "type": "string",
       "description": "Txhash (optional)"
      },
      "calldata": {
       "type": "string",
       "description": "Calldata (optional)"
      }
     }
    }
   },
   "additionalProperties": false
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/api-x402node-dev-ecf3e94c/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.x402node.dev](https://www.zero.xyz/host/api.x402node.dev/llms.txt)