Portea Medical India Backend Engineer Interview: Rounds, Questions and Preparation

What the job involves

As a backend engineer in digital health, you will build and maintain the server-side systems that power patient records, appointment scheduling, home healthcare visits, and billing. Day to day, you will write APIs, design databases, integrate with third-party services like payment gateways and SMS providers, and ensure data privacy and system reliability. Your work directly supports doctors, nurses, and patients across India, often in low-bandwidth or high-traffic conditions.

Role and technical knowledge

1. 1

   What is the difference between SQL and NoSQL databases, and which would you choose for storing patient appointment records and why?

   Explain that SQL offers strong consistency and relational integrity, which suits appointment records with clear relationships; NoSQL is better for unstructured or high-volume logs. Mention trade-offs like scaling and schema flexibility.

2. 2

   How would you design a REST API endpoint to fetch a patient's upcoming home visit schedule?

   Cover resource naming (e.g., /patients/{id}/visits), HTTP methods, pagination, filtering by date, authentication, and returning only necessary fields. Mention status codes and error handling.

3. 3

   Explain how you would implement authentication and authorization for a backend that serves both patients and healthcare providers.

   Discuss JWT or session-based auth, role-based access control (RBAC), secure password hashing, and token expiry. Emphasise that patients should only see their own data and providers only their assigned patients.

4. 4

   What are some key considerations for handling sensitive health data in India?

   Mention compliance with laws like the Digital Personal Data Protection Act, encryption at rest and in transit, audit logs, and access controls. Avoid claiming specific company practices.

Practical scenarios

1. 5

   A payment gateway integration for home healthcare bills is failing intermittently. How would you debug and fix it?

   Start by checking logs for error patterns, reproduce the issue, verify API keys and network timeouts, and add retries with idempotency. Suggest monitoring and alerting to catch future failures.

2. 6

   You need to send SMS reminders for upcoming appointments. Design a backend service that handles thousands of reminders per hour without duplicates.

   Propose a queue-based system (e.g., RabbitMQ or Kafka), a scheduler, and a deduplication key per appointment. Mention rate limiting and fallback if SMS provider fails.

3. 7

   A doctor reports that patient records are loading slowly. What steps would you take to improve performance?

   Check database indexes, query execution plans, and caching layers. Suggest pagination, lazy loading, and possibly denormalising read-heavy data. Mention measuring before optimising.

4. 8

   How would you handle a situation where a third-party lab report API returns data in an inconsistent format?

   Describe writing an adapter or mapper to normalise data, validating input, and logging mismatches. Suggest contract tests and fallback to manual review for critical fields.

Behavioural and HR

1. 9

   Why do you want to work as a backend engineer in digital health, and what excites you about this sector?

   Show genuine interest in improving healthcare access, mention scale and impact, and connect personal skills to the mission. Avoid generic answers about 'helping people' without specifics.

2. 10

   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, and the outcome. Highlight resourcefulness and ability to deliver under time pressure.

3. 11

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

   Focus on respectful discussion, data-driven decision-making, and willingness to compromise. Show that you prioritise project success over being right.

4. 12

   How do you ensure your code is reliable and maintainable when working in a fast-paced environment?

   Mention writing tests, code reviews, documentation, and following style guides. Give an example of a practice you consistently follow.

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, handle edge cases like no slots, and discuss time complexity. A simple linear scan is fine if justified; mention sorting if needed.

2. 14

   How would you detect and prevent duplicate patient registrations in a backend system?

   Suggest using unique identifiers like phone number or Aadhaar (with consent), fuzzy matching on name and date of birth, and database unique constraints. Discuss trade-offs between strict and lenient matching.

3. 15

   Write a SQL query to find the top 5 cities with the highest number of home visits in the last month.

   Use GROUP BY, COUNT, and ORDER BY with LIMIT. Mention filtering by date and joining tables if city is in a separate table. Explain how you would handle time zones.

4. 16

   Explain how you would design a rate limiter for an API that serves patient reports to prevent abuse.

   Describe token bucket or sliding window algorithms, where to store counters (e.g., Redis), and returning 429 status. Mention per-user and per-IP limits and graceful degradation.