Tokens

Transaction

A signed instruction that moves value or data on a blockchain, recorded permanently once miners or validators confirm it.

A transaction is the basic unit of activity on any blockchain. Someone signs it with a private key and broadcasts it to the network, then waits for it to land in a block. On Bitcoin it usually moves coins between addresses. On Ethereum it can also trigger a smart contract or mint a token.

Every transaction carries a fee that compensates the network for processing and storage. Once it is included in a block and buried under later blocks, it becomes effectively irreversible. There is no chargeback and no undo button. Send to the wrong address and the funds are gone for good.

Related terms

Transaction Fee

Paid to the network for processing a transfer, this charge rises and falls with how busy the chain is.

Confirmation

Each new block added on top of the one holding your transaction, deepening it and making reversal far harder.

Mempool

The waiting room where broadcast transactions sit before a miner or validator picks them for a block.

Address

A short string of letters and numbers that identifies where crypto can be sent on a blockchain.

All terms