What is Transaction?
A transaction is a digitally signed message that requests a change to blockchain state — transferring coins, calling a smart contract, or both. Once included in a block and confirmed, the change becomes part of the canonical history.
Why Transaction matters
Understanding Transaction is part of building a solid mental model of how Bitcoin, blockchain and Web3 systems actually work. Concepts in the Blockchain category sit at the foundation of the broader stack — get them right and the rest is far easier.
Learn this interactively
Reading the definition is a start. ZeroToBlock teaches concepts like Transaction through hands-on, browser-based simulations. Build the mental model by actually using it:
- Bitcoin 101 — interactive fundamentals course
- Bitcoin Proof of Work — mining, hashing and consensus
- Browse all interactive blockchain courses
Related terms
- UTXO (Unspent Transaction Output) — Bitcoin's accounting model: balances as a set of unspent outputs.
- Digital Signature — A cryptographic proof that the holder of a private key authorised a message.
- Block — A bundle of transactions added to the blockchain.
More blockchain terms
- Blockchain — A chained, append-only ledger of blocks.
- Consensus Mechanism — The rules a network uses to agree on the canonical chain.
- Fork — A divergence in the blockchain or its rules.
- Node — A computer participating in the blockchain network.
- Proof of Stake — A consensus mechanism where validators stake capital instead of burning energy.
- Reorganization (Reorg) — Replacing recent blocks with a competing chain that has more work.
- Block Time — Average interval between consecutive blocks.
- Genesis Block — The first block in a blockchain.
Keep exploring
Continue with the full blockchain glossary — 136 terms in total — or read the developer blog and FAQ for deeper context.