What is a hard fork in crypto?

What Is a Hard Fork in Crypto?

A hard fork is a protocol change that is not backward compatible. New blocks are valid under the new rules but rejected by nodes that did not upgrade. So the chain splits: one group follows the old rules, one the new. That can create two separate coins (e.g. Ethereum and Ethereum Classic after the DAO fork).

Why Hard Forks Happen

They can fix bugs, add features, or reverse a hack (controversial). Sometimes the community disagrees and part of it keeps the old chain. Not every hard fork leads to a valuable second coin. Many fade or are abandoned.

If You Hold Coins

You may hold the same balance on both chains after the fork. Exchanges decide whether to list and credit the new coin. Do not replay a transaction from one chain on the other without understanding replay protection. When in doubt, wait for clear guidance from your wallet or exchange.