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TXID (Transaction ID)

A TXID (transaction ID) is the unique string of letters and numbers that identifies one transaction on a blockchain. Pasting it into a block explorer shows the transaction's status, amount, fee and number of confirmations, so buyers can track crypto sent to their own wallet.

How a TXID works

A transaction gets its TXID when it is signed and sent to the network. On Bitcoin, the TXID is the double SHA-256 cryptographic hash of the transaction data, written as 64 characters using 0-9 and a-f. On Ethereum, the same thing is called a transaction hash and starts with 0x.

Because the ID is calculated from the transaction data, a different payment gets a different ID. Block explorers index every transaction, so anyone can search a TXID and see its status, block, addresses, amount and fee.

Example

The Bitcoin Pizza Day payment of 10,000 BTC on 22 May 2010 has the TXID a1075db5…d48d (shortened). Search the full ID in a Bitcoin block explorer and it still shows up, confirmed in block 57,043. You can view the Pizza Day transaction on mempool.space, a public block explorer.

Why it matters when you buy crypto

Crypto is delivered to the wallet address you provide. Once the transfer is on the blockchain, your wallet usually shows its TXID. Paste it into a block explorer for the same network to check the receiving address and confirmations. A Bitcoin TXID will not show up in an Ethereum explorer.

Learn how to send Bitcoin to a wallet and track the transfer, then buy crypto with Coinmama. If coins take longer than expected, read about blockchain delays and confirmations.

Risks and red flags

  • A TXID is not proof on its own. A TXID or screenshot from someone else can be fake or point to another address. Check it yourself.
  • Pending is not final. A transaction with zero confirmations can still be dropped or replaced.
  • Confirmed transfers cannot be undone. A TXID shows where coins went, but it cannot bring them back. See why blockchain transactions cannot be reversed.
  • TXIDs are public. Anyone with one can see the amounts and addresses involved. A TXID is fine to share with support; your seed phrase and private keys never are. Learn how to protect yourself from fraud.

Go deeper: How to send Bitcoin to a wallet, step by step.

Related terms

  • Confirmation A confirmation is the inclusion of a transaction in a block.
  • Mempool The mempool (memory pool) is the waiting area where each Bitcoin node holds valid transactions that have not yet been confirmed in a block.
  • Network Fees A network fee is the charge for processing a transaction on a blockchain, based on block space and demand, not on the amount sent.
  • Hashing Hashing is the process of turning any data into a fixed-length code, called a hash, with a one-way function that cannot be reversed.
  • Address A crypto address is a string of letters and numbers, like an account number, that identifies where coins should be sent on a specific blockchain.

Go deeper

Sources

  1. Bitcoin Developer Documentation: Glossary (TXID) (accessed )
  2. ethereum.org: Block explorers (accessed )
  3. bitcoin.org: Frequently Asked Questions (accessed )