All terms
How a distributed network agrees on which transactions are valid and in what order.
Consensus is the mechanism that lets thousands of independent computers agree without a coordinator. It answers who gets to add the next block and how disagreements resolve.
Proof of work spends electricity to make attacks expensive. Proof of stake requires capital at risk instead. Both make dishonesty cost more than it pays.
Bitcoin uses proof of work. Ethereum switched to proof of stake in 2022, cutting energy use by more than 99 percent.
That consensus means everyone agrees. It means the network converges on one history despite some participants being absent, slow or hostile. Disagreement is assumed; the algorithm is the part that resolves it.
Common questions
What happens if nodes disagree?
Is consensus the same as everyone agreeing?
Where this comes up on the site
The guides that actually use this word, rather than a list of everything we have written.
Where to go next
More technology terms
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