Go from confused
to confident.
System design, FDE, and DSA — three tracks that teach by running real artifacts, not by reading about them. Watch algorithms step through your data. Trace requests through real architectures.
Pick the role you're building toward.
Each track is its own product. The only thing they share is the approach: runnable artifacts, not slides.
Trace a real request through Instagram, Uber, and 26 more architectures. Watch failures play out in real time.
The role behind customer-facing AI. 48-hour demos, deploying into customer environments, productionizing without losing the room.
15 algorithm visualizers — sorting, searching, BFS/DFS, BST — with step-by-step animations, code panels, and spaced repetition.
Built for how engineers actually learn.
Every feature exists because static diagrams and slides leave too much to imagination.
Play, pause, scrub — or use ← → keyboard shortcuts. Every comparison, swap, and pointer move rendered live.
The active line highlights as you step. Switch languages. Copy in one click. Syntax-colored without a library.
SM-2 spaced repetition. Correct answers push cards out weeks. Wrong answers bring them back tomorrow.
Pick any two sorting algorithms, set an array, and watch them race. Step count comparison at the end.
Drag n from 1 to 500. Watch quadratic blow up while log-linear barely moves. Log-scale SVG chart.
A full SVG tree renderer: animated nodes, queue/stack strips, path tracing. Four tree algorithms.
From zero to confident in four steps.
System Design, Forward Deployed Engineering, or DSA. Each is its own product with its own depth.
A running system diagram, a cited FDE lesson, or an algorithm visualizer. Not a slide — something you can interact with.
Click, play, pause, scrub. Every decision point is annotated. Two explanation modes: technical and plain-English.
Quizzes after each algorithm. Spaced repetition surfaces weak spots. Interview mode for system design.
Ship knowledge. Not decks.
Pick any track and open a live artifact in under 60 seconds. No account required to start.
The byline on every system is a real engineer.
Every Reqflow explanation should be signed off by someone who has actually shipped that kind of system. Read a system you know, flag what's wrong, and your name goes on the page you reviewed.
Founding reviewers wanted. Be the first byline.