Nothing about a blockchain's rules lives in one place. They live in the software running on every <a href="/glossary/node/">node</a>, which is why changing a <a href="/glossary/protocol/">protocol</a> is a coordination exercise rather than a deployment. Developers can write the code, but each operator chooses whether to run it. A change only takes effect once enough of the network is enforcing it, and that persuasion phase is usually where the argument happens.
Soft forks are backwards-compatible: the new rules are a subset of the old ones, so blocks produced under them still look valid to older software. Hard forks are not. They permit something the old rules forbade, so a node that has not upgraded will reject the new blocks outright. If everyone upgrades, the chain simply carries on. If a meaningful group refuses, you get two chains sharing all history up to the split point and none afterwards, and anyone holding a balance at that moment holds it on both.
The word is overloaded, which causes confusion. A code fork means copying a project's source and launching something new with a fresh ledger, sharing no history at all. Splits also create genuine hazards: replay of transactions across the two chains, exchanges pausing withdrawals, and above all fake claim sites promising your split coins if you paste a seed phrase. Nothing legitimate ever asks for that, and our guide on <a href="/toolkit/how-to-spot-crypto-scams/">spotting crypto scams</a> covers the pattern.
Read forks as a feature rather than a failure. Because the rules are enforced by whoever runs the software, no single group can quietly redefine <a href="/glossary/consensus/">consensus</a>. Disagreement gets expressed openly, and sometimes expensively, instead of being settled behind closed doors.
Key takeaways
- Soft forks tighten rules and stay compatible with older software, while hard forks change them in ways that require every participant to upgrade.
- A lasting chain split only happens when a hard fork is contested, leaving two ledgers with identical history before the split and separate history after it.
- Any site offering to release your forked coins in exchange for a seed phrase or private key is a theft attempt, without exception.
Fork — frequently asked questions
Do I get free coins whenever a blockchain forks?
Only when a contested hard fork creates a second surviving chain, and only for balances you controlled at the split. Most forks are routine upgrades that produce nothing new. Where a split does happen, coins on the new chain are claimed with the keys you already hold; you never need to send funds anywhere or reveal a recovery phrase to receive them.
Why can't developers just push an update like a normal app?
Because there is no central server to push to. Each node operator, miner, validator, exchange and wallet decides independently which software to run, and a rule only becomes real once enough of them enforce it. That friction is deliberate: it means changes need broad agreement, and it is also why controversial upgrades can take years or end in a split.
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