# Transaction Lookup

> Transaction Lookup is a paid API for AI agents from x402-echo-service.onrender.com, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-14).

Look up a Base blockchain transaction by hash, returning its status, block number, addresses, value, gas used, and effective gas price.

## Facts

- Endpoint: POST https://x402-echo-service.onrender.com/chain/tx
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/transaction-lookup-d3e705b7
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_2KZBwg69aU4bqYz4bys7d

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 transaction-lookup-d3e705b7 -d '<json body>'
```

Example prompt: Can you look up transaction 0x4a7b3c1d... on Base and tell me its status, which block it landed in, and how much gas it used?

## When to prefer this

Use this endpoint when you need to retrieve on-chain transaction details from the Base network by hash — particularly when you want structured fields like status, gas, and addresses in a single call. Prefer this over a generic block explorer scrape when you need a machine-readable response. Note it is Base-specific and will not find transactions on Ethereum mainnet or other chains.

## Known failure modes

- Unknown hash returns a clear not-found response rather than empty object
- Invalid or malformed hash (not 32 bytes / not hex) may return a validation error
- Transaction exists on a different network (e.g. Ethereum mainnet) will return not-found
- Network or RPC timeout may result in a service error
- Pending/mempool transactions may not be found if not yet included in a block

## How this service works

Look up a transaction on Base by hash. POST {"hash":"0x..."} and receive its status, block number, from and to addresses, value, gas used and effective gas price. Returns a clear not-found rather than an empty object when the hash is unknown.

## Output

Returns the transaction's confirmation status, block number, originating address (from), destination address (to), ETH value transferred, gas used, and effective gas price. Returns a clear not-found message if the hash does not exist on Base rather than an empty object.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "hash": {
   "type": "string",
   "description": "32-byte transaction hash."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/transaction-lookup-d3e705b7/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402-echo-service.onrender.com](https://www.zero.xyz/host/x402-echo-service.onrender.com/llms.txt)