System Design Interviews
Senior-level mock loops with an AI interviewer that pushes back.
Drill system design the way real onsites run — whiteboard the architecture, defend trade-offs against an AI interviewer trained on senior-engineer patterns, and walk away with a scorecard that names the gaps in your design instincts.
Free intro · Pro at $9.99/mo unlocks unlimited mock interviews + scorecard PDFs
Who this track is for
- Mid-to-senior engineers prepping for L5/L6 / SDE-II / Staff loops.
- Engineers transitioning from feature work into architecture.
- Returners reactivating system-design intuition after years on a single stack.
Why Coachingle for System Design
What separates us from the problem-banks + recorded courses.
AI interviewer with a real persona
Not a script — an interviewer that asks why you picked Cassandra over Postgres, pushes on cache-invalidation, drills CAP tradeoffs. Six interviewer personas to rotate through.
Pattern library, not problem bank
Twitter timeline, URL shortener, Uber, Stripe webhook fan-out — every classic mapped to underlying primitives (sharding, queues, idempotency, eventual consistency).
Scorecard PDF
Four-evaluator panel grades you on requirement-gathering, scoping, depth, and communication. Share the PDF on LinkedIn — it renders as a signed scorecard.
Company-specific patterns
Pre-built research bundles for Google, Amazon, Meta, Stripe, and growing — they tilt the interviewer's questions and rubric toward what each company actually asks.
What you'll cover
Concept coverage drilled across cheatsheets, flashcards, quizzes, and mock interviews.
- ✓Requirement gathering + back-of-envelope scoping
- ✓CAP, PACELC, and consistency models
- ✓Sharding strategies + hot-partition mitigation
- ✓Caching layers (write-through, write-back, CDN)
- ✓Idempotent webhook + message-queue design
- ✓Database choice (RDBMS vs document vs columnar)
- ✓Search + ranking architectures
- ✓Real-time fan-out (push vs pull, hybrid)
Frequently asked questions
Will the AI interviewer actually push back, or just nod?
Push back. The four-evaluator system includes a 'Technical Expert' that flags hand-waves, a 'Silent Observer' that grades communication, and a 'Lead Interviewer' that asks the follow-up questions a senior engineer would. We don't ship soft-grading.
How long is a typical mock?
45 minutes — matches the loop you'd face onsite. You get a full transcript + scorecard PDF after.
What companies do you cover?
Pre-built research patterns for Google, Amazon, Meta, Apple, Microsoft, Stripe, Databricks, Snowflake, plus generic FAANG and unicorn rubrics. We add a new company per month based on user demand.
I'm targeting Staff/Principal — is this too entry-level?
We have a 'Staff+' rubric variant that grades on cross-system tradeoffs, organizational impact framing, and tech-strategy alignment. The interviewer goes harder on multi-quarter scenario planning.
Ready to drill System Design?
Free to start. No credit card. Pro at $9.99/mo unlocks the AI mock interview.