I Built My Own System Design Tool Because Nothing Free Was Good Enough

A few months ago I was working on a system architecture for a project and needed to diagram it out. I opened the usual suspects, draw.io, Excalidraw, Lucidchart. All either too generic, paywalled for the good stuff, or missing the cloud-specific components I actually needed. I just wanted a free tool built for engineers, with real AWS, GCP, and Azure components, that I could use without hitting a paywall mid-session. So I built one. The idea SysDesign started as a learning project as much as a product. I wanted to go deep on React Flow, understand how canvas-based UIs work under the hood, and ship something real at the end of it. The constraint I set myself was one week to get a working version out. The hardest part The canvas broke me for a bit. Getting drag and drop to feel right, handling node grouping, wiring up step undo/redo, making sure nothing felt laggy at scale. React Flow gives you a solid foundation but the moment you layer real interactions on top of it, edge cases pile up