What is Blockchain?

A blockchain is a database that many computers keep copies of and agree on together. Transactions are grouped into blocks, each cryptographically linked to the one before, forming a chain. Because thousands of participants hold and verify the same record, no single party can quietly change history, which makes the ledger trustworthy without a central authority.

This matters because it is the foundation everything else sits on. Tokens, staking, airdrops, and DeFi all exist as entries and code on a blockchain, and its openness is why anyone can verify balances and transactions.

Example: when you send crypto, the transaction is broadcast, validated, and permanently recorded in a block that everyone running the network can see and confirm.

Safety note: the blockchain’s transparency is a double-edged sword. It makes verification easy, but it also means transactions are public and irreversible, so mistakes cannot be undone and privacy is limited. Understanding this permanence is essential before you send funds or sign anything. Related terms include on-chain, consensus, node, and block explorer.