Rivery India Backend Engineer Interview: Rounds, Questions and Preparation

What the job involves

Backend engineers at fast-growing global tech companies build and maintain server-side logic, APIs, and data pipelines that power products used by customers worldwide. Day to day, they write clean, testable code in languages like Python, Java, or Go, design database schemas, integrate third-party services, and optimise systems for performance and reliability. In a smaller or fast-growing employer like Rivery India, you may also work closely with product, DevOps, and customer teams to ship features quickly and handle production issues.

Role and technical knowledge

1. 1

   What happens when a client sends an HTTP request to a backend API? Walk me through the flow.

   Cover DNS lookup, TCP handshake, request parsing, routing, business logic, database call, response serialisation, and status codes. Mention middleware for auth or logging.

2. 2

   How would you design a REST API for a simple task management app?

   Use resource-based URLs like /tasks and /tasks/{id}, correct HTTP methods (GET, POST, PUT, DELETE), status codes, pagination, and JSON request/response bodies. Mention authentication and idempotency for PUT and DELETE.

3. 3

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

   SQL for structured data, joins, and transactions (e.g., PostgreSQL). NoSQL for flexible schemas, high write throughput, or horizontal scaling (e.g., MongoDB, Cassandra). Give a concrete example like user accounts vs. clickstream logs.

4. 4

   What is indexing in a database and how does it affect query performance?

   Indexes speed up reads by creating a lookup structure but slow down writes and use extra storage. Mention B-tree indexes, composite indexes, and the trade-off of over-indexing.

Practical scenarios and problem solving

1. 5

   An API endpoint is returning 500 errors intermittently in production. How would you debug it?

   Check logs and error tracking (e.g., Sentry), reproduce with the same input, inspect database query performance, review recent deployments, and add temporary logging or metrics. Mention rollback if the issue started after a release.

2. 6

   You need to integrate a third-party payment gateway into your backend. What steps would you take?

   Read API docs, handle authentication (API keys or OAuth), implement webhooks for async events, add retries with exponential backoff, validate payloads, and never log sensitive card data. Mention sandbox testing first.

3. 7

   How would you optimise a slow SQL query that joins three large tables?

   Use EXPLAIN to find full table scans, add appropriate indexes on join and filter columns, avoid SELECT *, consider denormalisation or caching for read-heavy paths, and paginate results.

4. 8

   Describe how you would write a unit test for a function that calculates discounts based on user type and cart total.

   Cover normal cases, boundary values (zero total, maximum discount), and invalid inputs. Use a testing framework like pytest or JUnit, mock external dependencies, and assert both return value and side effects.

Behavioural and team fit

1. 9

   Tell me about a time you had to learn a new technology quickly for a project or hackathon.

   Use STAR format: describe the situation, the technology, how you learned it (docs, tutorials, pair programming), and the outcome. Show curiosity and ability to ship under time pressure.

2. 10

   Describe a situation where you disagreed with a teammate on a technical approach. How did you handle it?

   Focus on listening, presenting data or trade-offs, and reaching a decision together. Avoid blaming; show you can disagree without being disagreeable and commit to the final choice.

3. 11

   Give an example of a bug you introduced and how you fixed it.

   Pick a real but not catastrophic bug. Explain how you found it (tests, logs, code review), the root cause, the fix, and what you changed in your process to prevent similar issues.

4. 12

   Why do you want to work at a fast-growing global tech company like Rivery India rather than a large established firm?

   Show you understand the pace, ownership, and variety of a smaller or fast-growing employer. Mention eagerness to wear multiple hats, learn across the stack, and see your work impact customers quickly.

HR and career questions

1. 13

   What are your salary expectations for this backend engineer role?

   Research typical fresher salaries in India for global tech companies (e.g., 8-15 LPA depending on city and company size). Give a range and say you are open to the overall package including learning and growth.

2. 14

   Where do you see yourself in three years?

   Show a path from individual contributor to owning larger modules or mentoring juniors. Align with backend engineering growth: deeper system design, cloud, and performance skills.

3. 15

   Are you comfortable working in a hybrid or remote setup with occasional overlap with US or Europe time zones?

   Be honest about your flexibility. Mention you can manage async communication, block focus time, and attend early or late calls when needed for global team collaboration.

4. 16

   Do you have any questions for us?

   Ask about the tech stack, code review culture, on-call rotation, and how freshers are mentored. Avoid questions about salary or leave in this round; save those for HR if not already covered.