System design, dissected

Real production systems, taken apart. You break them, then fix them.

behindscale takes apart first-party engineering posts down to the one bottleneck that made each problem hard, and gives every system an interactive artifact. Sit in the engineer's seat: push it past its limit, see what breaks, pull the knob that fixes it — and read what the fix cost.

Live artifact · Priority-blind load shedding

Drag TRAFFIC past capacity, then flip SHED SMART — watch payments hold while batch jobs get shed first.

Five companies hit this same wall. Read the five →

Dissected from first-party blogs

  • Airbnb
  • Amazon (AWS)
  • Canva
  • Cloudflare
  • Datadog
  • Discord
  • DoorDash
  • Figma
  • GitHub
  • GitLab
  • Google
  • LinkedIn
  • Meta
  • Netflix
  • Notion
  • Pinterest
  • Reddit
  • Roblox
  • Segment
  • Shopify
  • Slack
  • Stripe
  • Uber

Built for Senior and Staff engineers

"Design Uber" gets you to Senior. Staff-level system design interviews ask what broke in production, what the fix cost, and what still gets through. That is exactly what these engineering posts contain — and what the artifacts let you feel instead of memorise.

Preparing for an interview or just getting better at the craft, the library is the same: 41 real systems, grouped by the wall each one hit, so you can see five companies answer the same question five different ways.

What's inside

Nine walls hit by three to five companies — fourteen in all.

Open any wall to see who hit it, how each team got past it, and what they gave up to do so.

Browse all 41 systems →