Blockchain Fundamentals
The technology under everything. Before you understand any coin, protocol, or DeFi product — you need to understand the blockchain they run on. Start here.
What is a blockchain?
The clearest plain-English explanation of what a blockchain actually is, what problem it solves, and why it matters — no technical background needed.
Read this first →What is a blockchain?
The core concept. What it is, what problem it solves, and why thousands of computers need to agree.
How blockchain works
Blocks, chains, hashes, nodes, and the process by which transactions become permanent.
Cryptography basics
Hash functions, public and private keys, digital signatures — the maths that makes crypto secure.
Smart contracts
Self-executing code on a blockchain. What they are, how they work, and what they make possible.
Nodes and validators
Who actually runs a blockchain network — full nodes, light nodes, validators, and miners.
Gas and transaction fees
Why transactions cost money, how fees are calculated, and why they sometimes spike dramatically.
Consensus mechanisms
How thousands of computers worldwide agree on one version of the truth. The full overview.
Proof of Work (PoW)
Bitcoin's mechanism. Mining, hash rate, difficulty, energy consumption — how and why it works.
Proof of Stake (PoS)
Ethereum's mechanism since 2022. Validators, staking, slashing, and why it uses 99% less energy.
Proof of History (PoH)
Solana's innovation. How a cryptographic clock enables 50,000+ transactions per second.
PoW vs PoS — comparison
Security, energy, decentralisation, speed — the real trade-offs between the two dominant systems.
Layer 1 blockchains
The base chains — Bitcoin, Ethereum, Solana, Avalanche. What makes each one different.
Layer 2 solutions
Built on top of Layer 1 to go faster and cheaper. Rollups, state channels, and how they connect back.
Layer 1 vs Layer 2 — comparison
When to use which, what you give up, and what you gain at each layer.
Sharding
Splitting the blockchain into parallel pieces. How it works and why it is hard to do securely.
Oracles
How blockchains get real-world data — prices, weather, sports results — without trusting a single source.
Account abstraction
Making crypto wallets work like normal apps — no seed phrases, social recovery, gasless transactions.
Custodial vs non-custodial
Who controls your keys — and why it is the most important security question in crypto.