# Calldata Selector and 32-Byte Word Splitter

> Calldata Selector and 32-Byte Word Splitter is a paid API for AI agents from twin.unykorn.org, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-03).

Splits raw EVM calldata hex into its 4-byte function selector and individual 32-byte ABI-encoded word chunks

## Facts

- Endpoint: POST https://twin.unykorn.org/calldata-split?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-03
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/calldata-selector-and-32-byte-word-splitter-52c25fa5
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_NF9rdHj23On7h8Fiv41co

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 calldata-selector-and-32-byte-word-splitter-52c25fa5 -d '<json body>'
```

Example prompt: Can you split this calldata into its function selector and 32-byte words: 0xa9059cbb000000000000000000000000ab5801a7d398351b8be11c439e05c5b3259aec9000000000000000000000000000000000000000000000000016345785d8a0000?

## When to prefer this

Choose this endpoint when you need a quick, pay-per-call decomposition of raw EVM calldata into its ABI components without running a local ABI decoder. Ideal for agents inspecting transaction inputs, debugging smart contract calls, or auditing calldata on the fly without needing the full ABI definition — particularly useful in pipelines where you already have other UnyKorn EVM tools (receipt lookup, ABI encoding, ENS resolution) and want a consistent x402 micropayment flow.

## Known failure modes

- Invalid or non-hex calldata string returns an error
- Calldata shorter than 4 bytes (missing selector) may fail parsing
- Payment failure or insufficient x402 funds blocks the request
- Malformed 0x prefix or odd-length hex string rejected by schema pattern
- Network timeout if the UnyKorn node is unavailable

## How this service works

Split calldata into its selector and 32-byte words — Genesis402 / UnyKorn Operator Network

## Output

Returns a JSON object with ok:true, the type field set to 'calldata-split', the parsed 4-byte function selector, and an array of 32-byte ABI word slots extracted from the calldata. Also includes a receipt with the transaction hash, USD amount charged, and a receipt ID for payment verification.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "params": {
   "type": "object",
   "properties": {
    "data": {
     "type": "string",
     "pattern": "^0x[0-9a-fA-F]*$"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "ok": true,
  "type": "calldata-split",
  "receipt": {
   "tx_hash": "0x<64hex>",
   "amount_usd": 0.002,
   "receipt_id": "g402-<16hex>"
  },
  "generated_at": "<iso8601>"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/calldata-selector-and-32-byte-word-splitter-52c25fa5/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from twin.unykorn.org](https://www.zero.xyz/host/twin.unykorn.org/llms.txt)