Practo Technologies Backend Engineer Interview: Rounds, Questions and Preparation

What the job involves

As a Backend Engineer at a digital health company like Practo, you will design and maintain server-side systems that power appointment booking, electronic health records, teleconsultation, and payment workflows. You will work on APIs, databases, and cloud infrastructure to ensure high availability, data security, and compliance with healthcare regulations. Day to day, you will collaborate with frontend, mobile, and product teams to ship features that improve patient and doctor experiences.

Role and Technical Knowledge

1. 1

   How would you design a REST API for booking a doctor's appointment?

   Cover endpoints for checking availability, creating a booking, handling conflicts, and returning confirmation. Mention idempotency and status codes.

2. 2

   What are the key considerations for storing patient health records in a database?

   Discuss encryption at rest and in transit, access controls, audit logs, and compliance with regulations like HIPAA or India's DPDP Act.

3. 3

   Explain how you would implement authentication and authorization for a telemedicine platform.

   Mention OAuth 2.0, JWT tokens, role-based access control for patients, doctors, and admins, and secure token storage.

4. 4

   How would you handle a scenario where a payment fails during an online consultation booking?

   Describe transaction rollback, retry logic, idempotent payment endpoints, and notifying the user with clear next steps.

Practical Scenarios

1. 5

   A critical API endpoint for fetching patient history is slow. How would you debug and improve its performance?

   Suggest profiling, checking database indexes, query optimization, caching frequent queries, and using pagination.

2. 6

   You need to integrate a third-party lab report service. How would you design the integration to be reliable?

   Cover asynchronous processing, retries with exponential backoff, circuit breakers, and storing raw responses for auditing.

3. 7

   How would you ensure that a scheduled job for sending appointment reminders runs reliably across multiple servers?

   Mention distributed locking, idempotent jobs, using a message queue, and monitoring for failures.

4. 8

   A security audit reveals that some API endpoints lack proper input validation. What steps would you take?

   Describe adding validation middleware, sanitizing inputs, using parameterized queries, and conducting a thorough review.

Behavioral and HR

1. 9

   Why do you want to work in digital health, and what excites you about companies like Practo?

   Show genuine interest in improving healthcare access and technology, and relate it to your skills and career goals.

2. 10

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

   Use the STAR method to highlight collaboration, your specific contribution, and the outcome.

3. 11

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

   Emphasize your learning process, resourcefulness, and how you applied the new skill effectively.

4. 12

   How do you handle tight deadlines or conflicting priorities?

   Discuss prioritization, communication with stakeholders, and maintaining quality under pressure.

Problem Solving and Coding

1. 13

   Given a list of appointment slots, write a function to find the earliest available slot for a given doctor.

   Clarify input format, consider edge cases like no slots, and aim for an efficient search or sort-based solution.

2. 14

   How would you detect and prevent duplicate patient records in a database?

   Discuss unique constraints, fuzzy matching on name and date of birth, and a review process for merging.

3. 15

   Design a rate limiter for an API that handles prescription requests.

   Explain token bucket or sliding window algorithms, and where to implement it (e.g., API gateway or middleware).

4. 16

   Write a SQL query to find the top 5 doctors by number of appointments in the last month.

   Use JOINs, WHERE with date filtering, GROUP BY, ORDER BY, and LIMIT. Mention indexing for performance.