SketchSystem
The whiteboard that teaches you system design.
An AI coach that reads your architecture — then explains, critiques, or draws with you.
No sign-up required · Open freeform canvas
Three ways to practice
Pick a graded challenge, design with components, or sketch freeform — the same coach follows you.
- 01 Challenges
LeetCode for system design — clear goals, constrained palette, graded submit with rubric feedback.
Browse challenges - 02 Structured
Drop services, stores, and queues from a full palette. Wire them up while the coach explains — or draws with you.
Start free design - 03 Freeform
Infinite Excalidraw-style whiteboard. You drive, or hand the pen to the AI.
Open freeform canvas
The diagram is the lesson
Critique lands on your boxes and arrows — not generic interview tips from a chat window that never sees the board.
Reads the canvas
Feedback is grounded in the architecture you drew, including what's missing.
Explains or critiques
Walk through every decision, or get sharp red-team feedback only — your call.
Draws with you
Ask for a URL shortener and watch real components land on the board, wired and editable.
Grades challenges
Deterministic goal checks plus a written rubric on your reasoning.
Free to practice. Pro when you're deep in prep.
Guests get daily AI turns with no account. Sign in to save sessions. Pro unlocks 500 AI turns/day and the full challenge catalog — $15/mo or $129/yr.