techdiagrams.net keeps an engineering team's design, data, docs and work in one workspace, so the reasoning behind a system lives beside the system rather than in a thread nobody can find. It holds a system and architecture diagram editor whose diagrams actually run, a database schema designer with SQL import and export, docs and design docs written where the systems are, and projects and boards whose tickets can carry the diagram, schema or page they change. Draw on a fast canvas with 112+ component icons plus official AWS, Azure, Google Cloud and Kubernetes icon packs — or describe your system in plain language and let the AI copilot draft it. Then go beyond pictures: attach behavior contracts and simulate load, crashes and failures against your design before you build it.
The editor is free. Pro adds the built-in AI (no API key needed), the real-run lab, and read-only share links.