Keka HR Software Engineer Interview: Rounds, Questions and Preparation

What the job involves

Software Engineers at Indian SaaS and B2B product companies build and maintain multi-tenant web applications that power business functions like HR, payroll, CRM, or accounting. Day to day, they write code for features such as employee onboarding workflows, attendance tracking, or invoice generation, fix bugs, review pull requests, and collaborate with product managers and QA. They also work on integrations, APIs, and performance improvements to keep the product reliable for hundreds of business customers.

Role and Technical Knowledge

1. 1

   What is multi-tenancy in a SaaS product, and how would you design a database schema for a payroll module that serves multiple companies?

   Explain that each customer's data is isolated, often using a tenant ID column or separate schemas. Mention trade-offs between shared and isolated databases for payroll data.

2. 2

   How would you model an employee attendance system where employees can clock in and out multiple times a day, and managers need monthly reports?

   Propose tables for employees, attendance events with timestamps, and a way to aggregate hours. Discuss indexing on employee ID and date for fast reporting.

3. 3

   What is the difference between authentication and authorization in a B2B HR tool where roles include admin, manager, and employee?

   Authentication verifies identity, authorization controls access. Give examples: a manager can approve leave but not change payroll settings, while an admin can do both.

4. 4

   Explain how you would design a REST API endpoint to fetch leave balance for an employee, including error handling and status codes.

   Use GET with employee ID, return 200 with JSON, 404 if employee not found, 401 if unauthorized, and 500 for server errors. Mention pagination if returning multiple records.

Practical Scenarios

1. 5

   A customer reports that their payroll run is slow and sometimes times out. How would you debug and improve performance?

   Start by checking database queries, add indexes, look for N+1 queries, and consider caching or background jobs. Also review server logs and monitor resource usage.

2. 6

   You need to add a new field to an existing employee table that already has millions of rows in production. How would you do it safely?

   Use a migration with a default value or nullable column, add the column without locking the table, and backfill data in batches. Test on a staging copy first.

3. 7

   Two modules, leave management and payroll, both need to know an employee's current salary. How would you avoid code duplication and keep data consistent?

   Create a shared service or API for employee compensation, use a single source of truth, and ensure updates go through that service. Mention transactions for consistency.

4. 8

   A bug causes incorrect tax deduction for a few employees in one company. How do you handle the fix and communicate with the customer?

   Reproduce the bug, write a test, fix the logic, and run a script to correct affected records. Inform the customer with a clear explanation and timeline for the fix.

Behavioural and HR

1. 9

   Why do you want to work in a SaaS product company like Keka HR rather than a services company?

   Show interest in building products that scale, solving recurring problems for many businesses, and learning about domains like HR and payroll. Avoid saying services is bad.

2. 10

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

   Use STAR method: describe the situation, the technology, how you learned it, and the outcome. Highlight self-learning and application.

3. 11

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

   Focus on listening, discussing pros and cons with data, and choosing the best solution for the team. Show respect and willingness to compromise.

4. 12

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

   Align your growth with the company's needs: becoming a strong product engineer, taking ownership of modules, and mentoring juniors. Avoid unrealistic titles.

Problem Solving and Coding

1. 13

   Given a list of employee clock-in and clock-out times, write a function to calculate total hours worked per employee per day.

   Clarify input format, handle overnight shifts, and use a hash map to group by employee and date. Discuss time complexity and edge cases like missing clock-out.

2. 14

   How would you find the first non-repeating character in a string, and why is this relevant to processing employee IDs or codes?

   Use a hash map to count frequencies, then iterate again to find the first with count 1. Mention O(n) time and its use in validating unique identifiers.

3. 15

   Write a SQL query to find the top 3 departments with the highest average salary in a company.

   Use GROUP BY department, AVG(salary), ORDER BY average DESC, and LIMIT 3. Mention handling ties and excluding null salaries.

4. 16

   How would you detect and remove duplicates from a list of employee email addresses while preserving the original order?

   Use a set to track seen emails and a new list for output. Explain O(n) time and why order matters for user-facing lists.