Blockchain hub
How blockchains work — and what they are good for
Blocks, consensus, smart contracts and layer-2 networks, explained with diagrams and everyday analogies instead of jargon.
In this hub
- Blocks and hashes
- Consensus mechanisms
- Smart contracts
- Layer-2 scaling
- Bridges and interoperability
- Real-world use cases
Overview
Blockchain in a nutshell
A blockchain is a database that many parties can share without having to trust one another. Each block contains a batch of transactions plus a cryptographic fingerprint of the block before it, so altering old records would mean redoing all the work that came after — and convincing the rest of the network to accept it.
Different networks make different trade-offs between security, speed, cost and decentralisation. Proof-of-work chains like Bitcoin prioritise security and simplicity; proof-of-stake chains like Ethereum add programmability through smart contracts; layer-2 networks batch transactions to cut fees. This hub explains those trade-offs so you can judge new projects on their design rather than their marketing.
What you'll learn
Key topics in Blockchain
Blocks and hashes
How data is chained together so that changing history becomes impractical.
Consensus mechanisms
Proof of work, proof of stake, and the trade-offs between them.
Smart contracts
Programs that run on a blockchain — and why bugs in them can be costly.
Layer-2 scaling
Rollups and payment channels that make transactions cheaper and faster.
Bridges and interoperability
Moving assets between chains, and why bridges are a common attack target.
Real-world use cases
Where blockchains help, and where a normal database is the better tool.
Latest guides
New in Blockchain
FAQ
Blockchain questions, answered
What is a blockchain in simple terms?
A blockchain is a shared record of transactions kept by many computers at once. New entries are grouped into blocks and linked together, which makes past records very hard to alter without everyone noticing.
What is the difference between proof of work and proof of stake?
Proof of work secures a network with computing power (mining). Proof of stake secures it with coins that validators lock up as collateral. Proof of stake uses far less energy; each model has different security trade-offs.
What is a layer-2?
A layer-2 is a network built on top of a main blockchain (layer-1). It processes transactions off the main chain and settles back to it, which lowers fees while borrowing the base chain’s security.
Are blockchain bridges safe?
Bridges add risk because they hold large pools of assets and rely on extra smart contracts or validators. Several of the largest crypto hacks have targeted bridges, so use well-established ones and move only what you need.
Related hubs