Tip 1: Prepare computer science concepts clearly with their practical applications.
Tip 2: Learn the technologies used in distributed systems.
Tip 3: Learn about Kafka and its use cases.
Tip 1: Keep your tech stack at the top of your resume for better visibility.
Tip 2: Highlight your achievements clearly to make your profile stand out.
Tip 1: Go through basic of distributed system.
Tip 2: Go through the CAP theorem and its practical application.
Tip 3: Go through the inner working of the load balancers.
This was a LLD round where I had to write working code for circuit breaker.
Design a Circuit Breaker mechanism that prevents cascading failures when calling an external dependency (e.g., API, DB, service).
It should:
Detect failures
Stop calls when failure threshold is reached
Recover automatically after some time
Core Functional Requirements
1. States of Circuit Breaker
The system must support three states:
CLOSED
All requests pass through
Failures are monitored
OPEN
All requests are blocked immediately
Fail-fast without calling downstream service
HALF-OPEN
Limited requests are allowed
Used to test recovery
2. Failure Handling
Track failures (exceptions, timeouts, error responses)
Maintain:
Failure count OR
Failure rate (over time window)
Transition to OPEN when:
Failure threshold is exceeded
3. Success Handling
Track successful calls
In HALF-OPEN:
If enough successes → move to CLOSED
If failure → move back to OPEN
4. Timeout Management
Each request should have a timeout
Timeout should be treated as a failure
Tip 1: Think in State Machine first (not classes).
Tip 2: Always address concurrency & edge cases.

Here's your problem of the day
Solving this problem will increase your chance to get selected in this company
What is the best case time complexity of Bubble Sort?