01Bitcoin Fundamentals
The Life of a Transaction
Follow one payment from your wallet to the blockchain.
Learning objective: Describe the six stages a payment passes through.
Explore
All 20 models
Each model is a working machine you can operate. Every one has three levels, Easy, Explore and Advanced, so you can start simple and go as deep as you like.
20 models
Bitcoin Fundamentals
What a transaction is, where coins really live, how blocks chain together and what a wallet holds.
01
04Bitcoin Fundamentals
The UTXO Machine
Bitcoin is not a balance. It is a set of spendable pieces.
Learning objective: Explain why spending part of a UTXO creates change.
03Bitcoin Fundamentals
The Chain of Blocks
Why changing the past breaks everything after it.
Learning objective: Explain why changing an old block invalidates the blocks after it.
06Bitcoin Fundamentals
Anatomy of a Wallet
A wallet holds secrets, not coins.
Learning objective: Explain that a wallet stores keys while coins live on the chain.
19Bitcoin Fundamentals
The SHA-256 Hashing Machine
A fingerprint for any data, computed step by step.
Learning objective: Explain why the same input always gives the same hash and a tiny change gives a very different one.
Security
Keeping keys safe, and why rewriting Bitcoin's history gets harder with every block.
07Security
The Recovery Phrase Machine
How twelve words can rebuild an entire wallet.
Learning objective: Explain why anyone with your recovery phrase controls your bitcoin.
08Security
Anatomy of a Signing Device
Why the screen on the device is the one you trust.
Learning objective: Explain why the private key never leaves the device.
15Security
The Bitcoin Security Arena
Why rewriting history gets harder with every block.
Learning objective: Explain why more confirmations make a payment safer.
18Security
The Lightning Security Machine
Why the latest channel state must be protected.
Learning objective: Explain why publishing an old channel state is risky for the cheater.
20Security
The Digital Signature Machine
Proving authorization without revealing the key.
Learning objective: Explain why a signature proves approval without exposing the private key.
Network
Nodes passing data, miners searching for blocks, the market for space in them, and Lightning payment channels on top.
11Network
The Global Bitcoin Network
Thousands of independent computers, no centre.
Learning objective: Explain why no single computer controls Bitcoin.
02Network
The Mining Machine
See the guessing game that secures every block.
Learning objective: Explain mining as repeated guessing that is hard to do and easy to check.
10Network
The Blockspace Market
Why fees rise and fall, and how miners fill a block.
Learning objective: Explain why limited block space creates a fee market.
16Network
The Lightning Channel Machine
Many payments, two blockchain transactions when closed cooperatively.
Learning objective: Explain why payments inside a channel do not each need a blockchain transaction.
17Network
The Lightning Routing Machine
Paying across a network of channels.
Learning objective: Explain how a payment can reach someone without a direct channel.
Economics
The issuance schedule, how monetary systems differ, and Bitcoin's history.
12Economics
The Bitcoin Halving Clock
Why new bitcoin arrives ever more slowly.
Learning objective: Explain why issuance decreases every 210,000 blocks.
13Economics
The Monetary Systems Machine
Two sets of rules for creating money, side by side.
Learning objective: Explain that money can be created by discretionary decisions or by fixed rules.
14Economics
The Bitcoin Time Machine
From a nine-page paper to a global network.
Learning objective: Name the main stages of Bitcoin's history.
Advanced
The difficulty feedback loop and multi-key custody, for learners ready for the mechanics.
05Advanced
The Difficulty Engine
How Bitcoin brings its rhythm back when mining power joins or leaves.
Learning objective: Explain why the puzzle difficulty changes.
09Advanced
The Multisignature Vault
Shared control: no single key can open it alone.
Learning objective: Explain why a 2-of-3 vault survives one lost key.
Beyond the models
Three pieces that connect the models: a map of the ideas, a lab for experiments and an observatory for the network.
Knowledge map
An interactive map of how Bitcoin concepts connect: prerequisites, five knowledge regions and the models that teach each concept.
Experiment Lab
Run Bitcoin experiments on one bench: what happens when half the miners disappear, when mining power doubles, or when demand rises. One seeded simulation, Bitcoin's real difficulty rule, stated assumptions.
Bitcoin Live
The state of the Bitcoin network on one observatory: latest block, intervals, difficulty, mempool, fees and estimated hash rate. Demonstration data by default; live data only after you agree.
No model matches both filters.
Learning times are estimates for trying all three levels. Previews are captured from the models themselves.