Welcome

Software architecture is the set of big decisions that shape a system and are hard to change later. This site explains those decisions in plain language.

Who it is for: developers, product owners, and anyone who joins a project and has to understand or start its architecture. You do not need to be an architect.

What you find here

• Concepts: short articles on one idea each, such as quality scenarios or architecture decisions. Every article starts with “In short” and lists the public sources it is written from.
• Guides: how to start the architecture of a project, step by step, and what to do when the basics are missing. Start with Step 4: Make quality requirements concrete.
• Review checklist: checks for an arc42 architecture document, grouped by section. See the arc42 checklist.
• Glossary: all concepts from A to Z.

For AI assistants: read llms.txt. Every page also exists as Markdown.