What I learn building exchanges, wallets and smart contracts, written up on Medium. Search or filter by topic.
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Field notes
by Harry Ermawan
8 notes inside. Pick one from the contents or turn the page.
8 min read
How the matching engine at the heart of an exchange pairs buy and sell orders, comparing FIFO time priority with pro-rata matching. Part one of my series on trading engines and HFT.
Read Trading Engine on Crypto Exchanges on Medium
4 min read
What actually happens when you create a wallet on EVM: non-deterministic versus deterministic wallets, and how HD wallets like MetaMask, Ledger and Trezor derive keys from a seed phrase.
Read How Wallet Works on EVM on Medium
9 min read
My notes on Solana core concepts, starting with accounts: the containers that hold data and tokens on chain, and how their structure compares to accounts on the EVM.
Read Account Concepts on Solana on Medium
5 min read
Personal notes on the most common smart contract vulnerabilities, starting with reentrancy, the bug behind the DAO attack, and how each attack works.
Read Vulnerabilities & Attacks of Smart Contracts on Medium
Bahasa Indonesia2 min read
An introduction in Bahasa Indonesia to the 2016 DAO attack: how recursive calls drained an Ethereum smart contract, and why an immutable contract could still be exploited.
Read Mengenal DAO Attacks pada Smart Contracts on Medium
5 min read
Why CSS methodology and architecture matter once a project grows, and how a clear structure cuts the code you write, the code you maintain and the work the browser does.
Read Styling (CSS) Methodology & Architecture is it important? on Medium
Bahasa Indonesia2 min read
An introduction in Bahasa Indonesia to blue green deployment: running the new version beside the old one so you can switch traffic predictably and roll back fast when something breaks.
Read Konsep Blue Green Deployment Strategies on Medium
5 min read
An engineer's view on measuring a product with analytics: setting up Google Tag Manager and Google Analytics in a React app to learn who your users are and what they do.
Read Measure your Internet Business with analytics using GTM & GA on React Apps on MediumPages 1 and 2 of 18Page 1 of 9