Service companies vs product companies
Service companies (TCS, Infosys, Wipro, Cognizant) hire for volume. Their interviews test basic aptitude and language syntax.
Product companies (Razorpay, Zerodha, Flipkart, Freshworks, Atlassian, Google) hire for capability. Their interviews test problem-solving, system thinking, and the ability to build production-quality code under constraints.
The preparation strategy is completely different.
The typical product company interview structure
Most Indian product companies follow a variation of this:
- Round 1: Online assessment — DSA problems (1–2 medium difficulty)
- Round 2: Technical phone screen — DSA + code quality
- Round 3: Machine coding round — Build a working feature in 60–90 minutes
- Round 4: System design (for experienced roles) — Design a scalable system
- Round 5: Hiring manager / culture fit
The 14 DSA patterns that cover 90% of problems
You don't need to solve 500 LeetCode problems. You need to deeply understand these patterns:
- Two pointers
- Sliding window
- Binary search (on answer space)
- BFS / DFS (graph traversal)
- Dynamic programming (1D and 2D)
- Backtracking
- Stack-based problems
- Heap / Priority queue
- Trie
- Union-Find (Disjoint Set)
- Topological sort
- Greedy algorithms
- Interval problems
- Matrix traversal
The machine coding round
This is where most candidates fail — and it's the round where product companies differentiate the most.
You are given a problem (e.g., "Build a parking lot management system" or "Build a rate limiter") and 60–90 minutes to write working code.
What they evaluate:
- Code organization and class design
- SOLID principles applied practically
- Edge case handling
- Clean, readable code (not clever code)
- Test cases (even basic ones show maturity)
- Ability to make trade-off decisions under time pressure
System design for experienced engineers
For roles at SDE-2 and above, system design rounds evaluate your ability to think at scale:
- Requirements gathering and scope definition
- High-level architecture with clear component boundaries
- Database schema design and access patterns
- API design (REST or event-driven)
- Scaling strategies (horizontal scaling, caching, CDNs)
- Trade-offs between consistency and availability
- Monitoring and observability
Common mistakes Indian engineers make
After working with hundreds of interview candidates, here are the patterns we see:
- Memorizing solutions instead of understanding patterns
- Ignoring time and space complexity analysis
- Writing code that works but is unreadable
- Skipping the machine coding round preparation entirely
- Not practicing system design until they reach SDE-2 interviews
- Focusing only on DSA while ignoring production engineering skills
How VidhaiX prepares candidates
Our career tracks include interview preparation integrated into the curriculum — not as a separate module, but as a way of thinking about code quality.
Students practice machine coding rounds weekly. System design is taught through building actual distributed systems. DSA patterns are learned in the context of real engineering problems, not abstract exercises.
The result: candidates who can both pass interviews and perform in the role — because the preparation mirrors the work.