A Bitcoin transaction ID, commonly called a TXID, is a unique identifier assigned to every transaction made on the Bitcoin network. It works like a digital receipt that allows anyone to locate and verify a specific transaction on the blockchain. Once a Bitcoin transaction is created and broadcast to the network, a cryptographic hash is generated from the transaction data. This hash becomes the TXID.

The TXID contains no personal information, but it links all the technical details of a transaction in one reference. By using a TXID in a blockchain explorer, users can see important data such as the sending and receiving addresses, the amount transferred, transaction fees, confirmation status, and the block in which the transaction was included. This transparency is a core feature of Bitcoin.

TXIDs are especially important for tracking payments. If a transaction is delayed or pending, the TXID allows users, exchanges, or merchants to check its status in real time. It is also used as proof of payment in disputes, customer support cases, and accounting or tax records.

It is important to note that a TXID is only generated once a transaction is properly broadcast. If a transaction is replaced or modified, such as through fee adjustments, the TXID may change. Overall, the TXID plays a crucial role in ensuring traceability, trust, and verification within the Bitcoin ecosystem.