Azure India Backend Engineer Interview: Rounds, Questions and Preparation

What the job involves

Backend engineers at global tech companies like Azure India design, build, and maintain server-side systems that power cloud services, APIs, and data pipelines. Day to day, they write scalable code, optimise databases, debug distributed systems, and collaborate with frontend and DevOps teams to ship reliable features. Freshers typically start with well-defined modules and gradually take ownership of larger services.

Role and technical knowledge

1. 1

   What happens when you type a URL into a browser and hit enter, from a backend perspective?

   Cover DNS resolution, TCP handshake, HTTP request, server-side routing, database queries, and response generation. Mention caching and load balancers if relevant.

2. 2

   Explain the difference between SQL and NoSQL databases. When would you choose one over the other for a cloud service?

   Discuss schema flexibility, scaling (vertical vs horizontal), consistency models, and use cases like transactions vs large-scale key-value stores. Relate to real cloud workloads.

3. 3

   How does a REST API work? What are idempotent methods and why do they matter?

   Describe HTTP methods, status codes, statelessness, and idempotency (GET, PUT, DELETE). Explain how idempotency prevents duplicate operations in retries.

4. 4

   What is a deadlock in operating systems? How can it be prevented in a backend service?

   Define the four conditions for deadlock, then discuss prevention techniques like lock ordering, timeouts, and resource allocation graphs. Give a database transaction example.

Practical scenarios

1. 5

   Your API suddenly starts responding slowly. How would you debug and fix it?

   Outline a systematic approach: check logs, metrics, and traces; identify bottlenecks (database, network, code); use profiling; and apply fixes like indexing, caching, or horizontal scaling.

2. 6

   You need to design a URL shortener that handles millions of requests per day. What components would you use?

   Cover hashing or base62 encoding, a database for mapping, caching for hot URLs, and load balancing. Mention trade-offs between consistency and availability.

3. 7

   How would you ensure a backend service is secure against common attacks like SQL injection and XSS?

   Discuss input validation, parameterised queries, output encoding, authentication/authorisation, and using security headers. Mention OWASP Top 10.

4. 8

   You are asked to add a new feature that requires a database schema change. How do you roll it out without downtime?

   Explain backward-compatible migrations, dual writes, feature flags, and gradual rollout. Highlight testing and rollback plans.

Behavioural and HR

1. 9

   Tell me about a time you worked in a team to solve a technical problem. What was your role?

   Use STAR format: describe the situation, your specific tasks, actions you took, and the result. Emphasise collaboration and learning.

2. 10

   Why do you want to work as a backend engineer at a global tech company like Azure India?

   Connect your interest in scalable systems and cloud computing to the company's impact. Mention specific technologies or projects that excite you.

3. 11

   Describe a situation where you had to learn a new technology quickly for a project.

   Show initiative and adaptability: how you identified resources, practised, and applied the learning to deliver results. Mention any measurable outcome.

4. 12

   Where do you see yourself in five years, and how does this role fit into that plan?

   Align your growth with technical depth and leadership. Show commitment to backend engineering and cloud technologies without sounding overly rigid.

Coding and problem solving

1. 13

   Given an array of integers, find two numbers that add up to a target sum. Discuss time and space complexity.

   Explain the hash map approach for O(n) time and O(n) space. Mention brute force as a baseline and edge cases like duplicates.

2. 14

   How would you reverse a linked list iteratively and recursively?

   Walk through pointer manipulation for iterative, and base case plus recursion for recursive. Discuss trade-offs in space complexity.

3. 15

   Implement a function to check if a binary tree is a binary search tree.

   Use in-order traversal or recursive range checks. Clarify handling of duplicates and empty trees.

4. 16

   Design a rate limiter for an API. What data structures would you use?

   Cover token bucket or sliding window with Redis. Discuss distributed coordination, accuracy, and performance.