Library · Crypto, word by word · Transactions and fees
What is a transaction hash?
A transaction hash (also called a transaction ID or TXID) is a unique string of letters and numbers generated when a transaction is submitted. It works like a receipt number: anyone can paste it into a block explorer to look up that exact transaction.
What it means for you
When a payment is disputed or a deposit has not arrived, the transaction hash is what an exchange or recipient asks for. It is already public, and sharing it gives no one the ability to move your funds.
A common mistake: “Someone who has my transaction hash can take my funds.”
In fact: A transaction hash is a public lookup key for something that already happened; it cannot sign anything or move funds. The private key or seed phrase is what has to stay secret.
How it works
The hash is computed from the transaction's own data, so it is fixed by what was signed rather than assigned by any service. On Bitcoin the TXID is derived from the hash of the complete transaction, and later transactions cite it, together with an output index, to point at the coins they spend. On Ethereum a transaction hash is generated cryptographically when the transaction is submitted, the first step of its lifecycle, and explorers use it as the lookup key for status, block, fee and addresses.
Sources: ethereum.org: Transactions, ethereum.org: Block explorers, Bitcoin developer guide: Transactions · checked 4 October 2026
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