1. Technical Round (Round 1) – Rate Limiter

Focused on designing/implementing a rate limiter.

Likely covered concepts such as:

Token bucket / Leaky bucket

Sliding window counters

Distributed rate limiting

Handling bursts, fairness, and scalability

API throttling use cases

1. Onsite Round (Round 2) – hiring manager

Discussion around:

Problems you have tackled in past roles

Depth of understanding in streaming and messaging systems, including:

Event-driven architectures

Kafka / Kinesis / Pulsar concepts

Consumer groups, partitioning, backpressure

At-least-once vs exactly-once delivery

Real-time vs batch processing

1. Design Round – Scalability & data Structures

Worked on designing a system with:

Scalability considerations (high throughput, fault tolerance, load balancing)

Appropriate data structures and algorithms

Possibly included:

System components and communication patterns

Handling large-scale data or high read/write loads

Trade-offs between latency, consistency, and complexity

“can you explain scaling in a concrete, business-focused way?”