What Is A Transaction ID?
A bitcoin transaction ID, also known as a TXID or transaction hash, is a unique 64-character string that identifies a specific transaction on the blockchain. Each TXID is always 64 characters long (32 bytes) and uses the base 16 hexadecimal format using the numbers 0-9 and the lowercase letters a-f.
A TXID looks something like this: a1075db55d416d3ca199f55b6084e2115b9345e16c5cf302fc80e9d5fbf5d48d
You can think of a TXID like a fingerprint – it uniquely identifies a particular transaction without revealing any sensitive information about the sender or receiver.
Creating A TXID
A Bitcoin transactionWhat Is A Bitcoin Transaction? A Bitcoin transaction is the transfer of bitcoin from one address to another address or when new bitcoin is created. Transactions can also be the... is just a bunch of data that describes how bitcoin is transferred from one sending address (or multiple sending addresses) to a receiving address (or multiple receiving addresses). You can think of a transaction as a series of inputs and outputs. All of this raw transaction data is then hashed twice using a SHA-256 hashing algorithm to generate a unique 64 digit transaction ID.
When you sign a transaction, you are actually signing the TXID. This means that if any part of the transaction changes, the transaction ID changes which also changes the signature, and the entire transaction becomes invalid.
Looking Up A TXID
With a TXID, you can look up a transaction using a bitcoin full node or a block explorer.
If you would like to look up some transactions on the blockchainWhat Is The Blockchain? The blockchain is the public record of bitcoin transactions, which are organized into blocks that are all chronologically linked to one another. Because every block is..., you can use a block explorerWhat Is A Block Explorer? A block explorer is a browser for viewing or "exploring" all of the information on the bitcoin blockchain. With a block explorer, you can view... to search for a TXID to view all of the information about that particular TXID.
Here are some famous TXIDs that you can look up.
The First Bitcoin transaction ever created in the Genesis block: 4a5e1e4baab89f3a32518a88c31bc87f618f76673e2cc77ab2127b7afdeda33b
More than 161,000 bitcoin were transferred for a little more than 10,000 satsWhat Is A Satoshi? A Satoshi (sat or sats for short) is the smallest unit of a bitcoin. 1 Satoshi is a hundred millionth of a BTC (1 sat =...: b36bced99cc459506ad2b3af6990920b12f6dc84f9c7ed0dd2c3703f94a4b692
If you ever send or receive bitcoin yourself, you can look up your transaction ID to see more information about the transaction like whether or not it has been confirmed and added to the blockchain or what fee rate was paid.