Practical engineering, one day at a time.

Expona publishes practical development write-ups from engineers who build and run real platforms. Each article starts from a real problem — an API that had to scale, a deployment that failed, a design decision that needed defending — and explains what worked, what did not, and why.

Our 100-day series take one stack from first setup to production, one focused article a day: .NET and ASP.NET Core, NestJS, React and Next.js, AWS, Kafka, Flutter, AI and machine learning, and more. Every article includes code you can reuse and the trade-offs behind each choice.

The library holds 3,000 development write-ups, with 30 series of 100 days each and 1 interview series. Series running now include Apache Spark & Data Engineering, AWS for Developers, Design Patterns in Practice, Elasticsearch & Search Engineering and Engineering Craft. Browse by topic: AI & Machine Learning, Architecture & Design, Backend Engineering, Cloud & DevOps, Data & Streaming, Frontend & Web, Leadership & Career, Mobile.

Articles are reviewed by an editor before they are published and kept up to date as tools change. Read more about us, get new articles by email, or tell us what to write next.