FamPay | Tech Lead | Sept 2026 | Rejected
- Experience
- 8 years
- Posted
- 5 Oct 2026
Summary
I interviewed for a Tech Lead position at FamPay in September 2026, faced a rate limiter LLD and was rejected the next day.
How it went
Company: FamPay Role: Tech Lead
Current Org: Startup College: Tier-1 YOE: 8+ Current Comp: ~65L (Cash component) + ESOPs
Round 1 - HR Intro Call Basic intro, past projects overview, and why I am looking to switch.
Round 2 - LLD Basic intro followed by the main question: Design a rate limiter.
- First, we discussed available algorithms and their use cases.
- They asked me to pick any algorithm. The rate limiter needed to support separate limits for separate users.
- I picked the sliding window counter. I knew the logic: we maintain two counters and calculate the exact usage from those two counters using the formula:
current_count + (previous_window_percentage * previous_count). - Self-reflection: It has been a long time since I wrote proper core logic by hand after adopting Claude for coding. I wasn't able to write the correct logic. I moved on and wrote the user-level threshold logic and other components, but was not able to solve the core algorithm completely.
- Time ran out and I was not able to fix my logic in the rate limiter. I really should have picked the sliding log approach for ease.
When the interviewer asked if I had any questions at the end, I just said "no questions" as I knew I would be rejected, and ended the call.
Verdict: Rejected the next day.
Questions asked (1)
- 01
Design a Rate Limiter
System Design
Design a rate limiter that supports separate limits for separate users. Discuss possible algorithms (e.g., sliding window counter, sliding log) and implement the chosen approach. The implementation should track usage per user and enforce the specified limits.