# EVM Calldata & Transaction Decoder / x402 Settlement Verifier

> EVM Calldata & Transaction Decoder / x402 Settlement Verifier is a paid API for AI agents from workbot1.oddsys.org, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-15).

Decodes a Base-mainnet transaction hash or raw EVM calldata into human-readable form — function selector, matched signature, named arguments, and ERC-20/USDC transfer events — and can verify an x402 payment settlement receipt in one call.

## Facts

- Endpoint: POST https://workbot1.oddsys.org/decode-tx
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/evm-calldata-transaction-decoder-x402-settlement-verifier-083ca64c
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_kakU_wrac16Rhb_WUnE-r

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-transaction-decoder-x402-settlement-verifier-083ca64c -d '<json body>'
```

Example prompt: Can you decode this Base mainnet transaction for me — 0x4a3b...c9f2 — and tell me what function was called, what the arguments were, and whether it contains a USDC transfer so I can verify the x402 payment settlement?

## When to prefer this

Choose this endpoint when you need a single-call solution to decode Base-mainnet EVM calldata or verify an x402 payment settlement receipt — it combines calldata decoding and ERC-20 event extraction in one step, saving round trips. Prefer it over raw RPC calls when you need human-readable argument names and USDC transfer verification without setting up local ABI parsing infrastructure.

## Known failure modes

- Transaction hash not found on Base mainnet — returns 404 or not-found error
- Calldata does not match any known ABI signature — selector returned but arguments may be unresolved
- Transaction is pending/unconfirmed — receipt events unavailable
- Malformed calldata or invalid hex — parsing error returned
- Rate limit or payment failure for the $0.005 USDC per-call fee

## How this service works

Decode EVM calldata or a Base-mainnet transaction into human-readable form: function selector, matched signature, named args, plus ERC-20/USDC transfer events from the receipt — verify an x402 settlement receipt (tx hash in, payer/payee/amount out) in one call.

## Output

Returns the decoded function selector, matched ABI signature, named and typed arguments, and any ERC-20/USDC Transfer events found in the transaction receipt, including payer address, payee address, and USDC amount — all in structured, human-readable JSON.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "data": {
   "type": "string",
   "description": "0x-prefixed EVM calldata to decode (offline)."
  },
  "txHash": {
   "type": "string",
   "description": "0x-prefixed Base-mainnet transaction hash — fetches, decodes, and lists ERC-20/USDC transfer events (x402 receipt verification)."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/evm-calldata-transaction-decoder-x402-settlement-verifier-083ca64c/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from workbot1.oddsys.org](https://www.zero.xyz/host/workbot1.oddsys.org/llms.txt)