Part 1: Blockchain foundations

Nine lessons that take you from "what is money, to a computer?" to how your program talks to a blockchain. No prior knowledge of cryptocurrency, cryptography or networking is assumed.

#	Lesson	The question it answers
1	Money, ledgers and blockchains	What problem does a blockchain solve, and for whom?
2	Hashes, keys and signatures	How can anyone check who approved a payment, without trusting anyone?
3	Wallets, keys and addresses	What does a wallet really hold, and where do addresses come from?
4	Coins, tokens and exact amounts	What is being moved, and how do you count it without losing a cent?
5	Transactions	How does "pay Bob" become something the network accepts?
6	Blocks, confirmations and finality	When is a payment really, irreversibly done?
7	Accounts, UTXOs and transaction order	How does a chain stop the same payment from happening twice?
8	Fees and fee markets	Who gets paid to process a payment, and how much?
9	Nodes, RPC and providers	How does your code actually reach a blockchain?

When you finish, Part 2: Engineering for money turns to the engineering problems that come with moving money over an unreliable network.