Learn system design
by watching it break.

Build an architecture, send real traffic through it, and see exactly where it fails and why. Then fix it, the way you'll have to in the interview.

Run a Simulation Watch the demo

No setup. Run your first simulation in seconds.

What senior engineers
look for in a design.

Every design you submit is scored on the five things interviewers check, the same rubric big-tech interview loops use.

P
Problem UnderstandingDid you clarify scope, scale, and constraints before drawing anything?
R
Requirement AnalysisDid you capture functional and non functional requirements?
I
Identification of ComponentsDid you identify the right services, boundaries, and data flows?
S
System ArchitectureIs the design coherent, scalable, and resilient under realistic load?
M
Mitigations & TradeoffsCan you defend your decisions and reason through alternatives?

Nothing fails on a whiteboard.
Everything fails under load.

PRISM runs your design and shows what happens next: which part gives out first, how badly, and why.

Single Point of Failure

No redundancy. One node goes down, the whole system does.

100% downtime risk

Database Saturation

Write throughput exceeded. Queries queue faster than they drain.

P99 > 2,000ms

Queue Overload

Consumers can't keep up. Backpressure cascades upstream.

Depth: unbounded

Latency Spike

One slow dependency drags down your entire response time distribution.

Tail latency +800ms

Replica Lag

Primary/replica gap grows under write load. Reads return stale data.

Lag: 4.2s behind

Throughput Collapse

Circuit breaker trips. Requests rejected at the edge. System unavailable.

0 rps accepted

Design, simulate, score.
Then do it again, better.

01

Design your system

Drag real components onto the canvas and wire them up, the way you would on the whiteboard.

02

Run live simulation

Send real traffic through it. Watch requests flow, see where they queue, and find what breaks first.

03

Get your score

See what held up and what didn't, what to change, and whether the design is ready for an interview.

Start Free Evaluation

From the building blocks
to real-world systems.

The System Design Roadmap takes you from the fundamentals to production systems in five phases, in an order that makes sense.

  1. Learn the concept

    Short explanations, each with a diagram you can play with.

  2. Build with it

    Use what you just learned in a real architecture, straight away.

  3. Test your design

    Run traffic through it and see what breaks under load.

Start the Roadmap

20+ concepts, 40+ interview questions, about 25 hours end to end.

Watching isn't practising.
Building is.

What you get Videos & books PRISM
Learn concepts Passive videos Build while you learn
Test your design No validation Instant checks as you design
Simulate traffic Not possible Real traffic, simulated
Show failures Theoretical only The exact part that breaks
Feedback Delayed, subjective Immediate, from the simulation
Confidence Guesswork A score you can track

Every decision costs something.
PRISM shows you what.

Every design decision has a consequence at scale. PRISM doesn't just score your system, it shows which decisions hurt you and exactly what they cost.

  • Scalability vs. simplicity
  • Consistency vs. availability
  • Latency vs. throughput
  • Cost vs. reliability
  • Sync vs. async processing
See your tradeoff score →
Tradeoff Analysis AI Evaluation
Decision under review
"You chose synchronous DB writes without a write through cache."
Consequence at 50k RPS
Write latency
1,240ms
DB queue depth
12,400
Error rate
4.2%
Consider async writes via write behind cache to decouple DB pressure.
Engineers from these companies train with PRISM

Your system is only as strong
as its weakest node.

Find it. Fix it. Think in systems.

Run your first simulation Take the full evaluation

Free to start. 5 simulations/month on the free plan.