Nothing on the site is locked right now. All 57 simulations, all 12 interview questions, every scenario, unlimited review cards.
No plan, no card, no sign-up to run anything. On 1 September 2026 the plans below start and the free tier becomes the one described in the first card.
- Foundation simulations — client-server to LSM trees
- Two full interview rooms: URL shortener & rate limiter
- The learning path & glossary
- 10 review cards a day
- Advanced simulations (distributed systems & beyond)
- The other 10 interview rooms
- Everything on the site, unlocked
- All 12 interview rooms, every scenario
- All 57 simulations, including distributed systems
- Unlimited review cards
- Covers a full interview-prep cycle
- Everything on the site, unlocked
- All 12 interview rooms, every scenario
- All 57 simulations, including distributed systems
- Unlimited review cards
- Good for a final-week sprint
Prices in INR, inclusive of taxes. Cancel in one click — access runs to the end of the period.
What’s free, what’s paid
This is the split from 1 September 2026. Until then, everything in the paid column is free as well.
| On the site | Free | Paid |
|---|---|---|
| Foundation simulations (bytes → storage engines) | ✓ | ✓ |
| URL shortener & rate limiter interview rooms | ✓ | ✓ |
| Learning path & glossary | ✓ | ✓ |
| Review cards | 10 / day | unlimited |
| Advanced simulations — consistent hashing, Raft, quorums, gossip… | — | ✓ |
| The other 10 interview rooms — chat, news feed, ride-share, video… | — | ✓ |
| Every scenario & epoch in every room | — | ✓ |
Questions
Yes. Every simulation and every interview question is open until 1 September 2026, with nothing to pay and no card to enter. You can run the simulations without an account at all.
The plans above start. The free tier stays free and keeps the foundation simulations, two full interview questions, the learning path and the glossary — the first card lists it exactly. Nothing you have already worked through disappears.
Yes — UPI and UPI Autopay for subscriptions, plus all major cards. Powered by Razorpay.
Nothing but the length. Both unlock the entire site. Quarterly covers a typical interview-prep cycle and works out to ₹333 a month.
Anytime, in one click. You keep access until the end of what you’ve paid for.
If the first week doesn’t work out, write to us within 7 days and we’ll refund it — no questions asked. See the refund policy.