# POST /monitor_tx
**Monitor USDT Transaction**

Begin tracking a USDT transaction. Callbacks are sent to your store's endpoint whenever the transaction status changes.

Authentication: Bearer token required (Authorization: Bearer YOUR_API_KEY)

## Request Body (application/json)
- `txhash` — string (required): The transaction hash to monitor.
- `crypto` — string, enum("USDT") (required): The cryptocurrency used (USDT).
- `match_callback` — string (required): String to match part of your store's callback URL. Used to identify the correct store when you have multiple.
- `testnet` — integer, enum(0, 1), default: 0 (required): Network. `0` = mainnet (Ethereum), `1` = Sepolia testnet.

## Responses
- 200: Transaction successfully monitored.
  - `status` (integer): Current status of the transaction. `-1` = Reverted, `0` = Unconfirmed, `1` = 1 confirmation, `2` = 2 confirmations (final).

Full reference: https://developers.blockonomics.co/docs/merchants/post_monitor-tx