Mastercard SDE-1 Interview Experience — PICT | 2026

1. Company and Role

• Company: Mastercard

• Role: Software Development Engineer 1 (SDE-1)

• Graduation Year: 2027

• Branch: Computer Engineering

• College: Pune Institute of Computer Technology (PICT)

2. A Little Background

My Mastercard journey actually started a year before this interview.

On 25 August 2025, I participated in Mastercard Code for Change 2.0, where I was among the top 200 participants out of 1,500+ applicants.

After the hackathon, Mastercard offered internships to a few selected students. Unfortunately, I wasn't among them. It was honestly a very disappointing moment for me because I had hoped that the hackathon would lead to an internship opportunity.

A year later, during my final year, Mastercard came to our campus with another opportunity — this time for an SDE-1 role.

This felt like another chance to prove myself.

3. Application & Shortlisting Process

This was a pool-campus drive, rather than a drive restricted to a single college.

Students from colleges including COEP, PICT, SPIT, VIT, Cummins, and others participated in the process.

For this drive, students from CE, IT and AIDS branches were eligible.

Timeline

• 2 September 2026: Online Assessment

• 4 September 2026: Interview shortlist announced

• 7 September 2026: Interviews conducted at Cummins College

• 7 September 2026: Final selection

From PICT, 35 students were shortlisted for the interviews.

4. Online Assessment

Platform

HirePro

Mode

On-campus

Duration

1 hour

The OA consisted of 2 DSA questions.

Question 1 — Trie

The first question was based on a Trie data structure.

Question 2 — Constrained BFS

The second question was a more interesting graph/BFS-based problem.

We were given infected elements and had to figure out how to enclose the infected elements using the minimum number of walls while maximizing the number of safe elements.

The problem involved thinking about BFS with constraints and optimization, rather than being a straightforward traversal problem.

The shortlist was announced on 4 September, and 35 students from PICT made it to the interview stage.

5. Interview Process

There were 4 rounds:

1. Group Discussion

2. Technical Interview 1

3. Technical Interview 2

4. HR Interview

The interviews were conducted on 7 September 2026 at Cummins College.

Round 1 — Group Discussion

Topic: "AI — Boon or Threat?"

Our group consisted of 11 candidates.

The GD was fairly straightforward in terms of the topic, but with 11 people in the group, managing the flow of the discussion was important.

I took the initiative to:

• Start the discussion

• Participate actively and help maintain the flow

• Ensure that different viewpoints could be discussed

• Conclude/end the discussion

For me, the biggest takeaway from this round was that in a GD, it isn't necessarily about speaking the most. Being able to communicate your thoughts clearly, listen to others, build on their points, and help move the discussion forward is equally important.

Round 2 — Technical Interview 1

The interviewer was a Senior Software Engineer with 10+ years of experience.

The round started with my introduction.

I introduced myself with my name, college and branch, and briefly talked about my experiences with Code with Cisco and Mastercard Code for Change 2.0.

The interviewer picked up on these experiences and asked me about them.

After discussing my experiences, we moved into the technical questions.

Question 1 — String Compression

I was given the string:

text
1aaabbcccceeddd

and asked to produce:

text
13a2b4c2e3d

I explained my approach of traversing the string while keeping track of the previous character and its frequency.

Whenever the character changed, I would append the count followed by the character to the resulting string.

The important part here was being able to clearly explain the logic rather than immediately jumping into code.

Question 2 — Stack

The interviewer then asked me a stack-based question.

I discussed the approach and worked through the problem during the interview.

Question 3 — Decimal to Binary

The interviewer then asked me to convert a decimal number to binary.

He deliberately gave:

text
113 → 1011

I immediately noticed that something was wrong.

11011

I pointed this out to the interviewer and then explained the approach I would use for converting a decimal number into its binary representation.

This was a small moment, but it reinforced the importance of not blindly accepting the interviewer’s assumptions. If something doesn't look right, it is worth politely pointing it out and explaining why.

Other Discussion

Towards the end of the technical round, the interviewer asked me whether I was interested in higher education, Master's, or further studies.

Overall, this round was a combination of DSA/problem-solving, basic programming concepts, and getting to know my background and future plans.

Round 3 — Technical Interview 2

The second technical round started with my introduction as well.

After that, the interviewer went through my resume and asked me to rate myself in all the programming languages mentioned on it.

I tried to be honest about my actual proficiency.

I explained that:

• C++ — My primary language for DSA and competitive/problem-solving questions.

• Python & JavaScript — Mainly used for development.

• Java — Something I was still learning and wasn't as comfortable with.

This honesty became relevant later in the interview.

Question 1 — Sorting an Extremely Large File

This was probably one of the trickier questions for me.

The interviewer asked me to imagine that there were infinitely many comma-separated numbers stored in a very, very large text file, and asked how I would sort them.

At first, I immediately started thinking about standard sorting algorithms:

• Merge Sort

• Insertion Sort

• Quick Sort

However, the interviewer then added a constraint:

We cannot use extra space at all.

At this point, I became a little nervous because the constraint completely changed the problem.

I started thinking about ways to deal with data that was too large to handle normally and suggested an approach involving chunking and embeddings.

Looking back, my answer was definitely vague, but it reflected my attempt to reason about handling extremely large data under memory constraints.

The important lesson for me from this question was that interviewers can introduce constraints that force you to rethink an otherwise familiar problem.

Question 2 — Java

code

1.equals()

vs

code

1==

The interviewer then asked me about the difference between:

java
1.equals()

and

java
1==

I wasn't able to answer this correctly.

At that point, my limited experience with Java became evident. I had already mentioned that Java was something I was learning, so the interviewer understood where I stood.

Instead of continuing with Java-specific questions, he asked me something more general:

"How do you learn new technologies?"

I explained that I rely on resources such as:

• Official documentation

• Technical forums

• Online resources

• Learning by actually working with the technology

This was a good reminder that being unable to answer one question doesn't necessarily end an interview. How you respond after not knowing something can also matter.

Question 3 — System Design

The interviewer then gave me a system-design question:

Design a system for Pune University, where multiple colleges are part of the university.

At that point, I wasn't particularly familiar with answering system-design questions in an interview setting.

I therefore approached the problem using the architectural concepts I was comfortable with.

I discussed:

• Frontend

• Backend

• Database

• APIs/API endpoints

• Database schemas

• Communication between different components

It wasn't a highly sophisticated system-design answer, but I tried to build the architecture logically using the concepts I knew.

This was probably the biggest learning point from the round for me: you may be asked about areas that you haven't specifically prepared for, so being able to construct an answer from first principles is extremely useful.

Round 4 — HR Interview

The final round was a fairly standard HR interview.

The interviewer asked questions related to:

• Personal information

• Parents/family

• 10th standard

• 12th standard

• Previous experiences

• Hackathons

• Code with Cisco

• Mastercard Code for Change 2.0

Since my previous Mastercard experience was already on my resume, the Code for Change 2.0 experience naturally became part of the discussion.

6. The Result

My HR round was conducted at around 7:00–7:30 PM.

We were initially told that the results would be announced the next day.

So I assumed that I would have to wait overnight to find out the result.

But things turned out very differently.

At around 9:00 PM, just about 1.5 hours after the HR round, the results were announced.

There were 11 selected candidates.

And fortunately...

My name was on the list.

After what had happened with Mastercard Code for Change 2.0 the previous year, seeing my name there was a particularly satisfying moment.

In 2025, I had made it to the top 200 participants out of 1,500+ applicants for Mastercard Code for Change 2.0, but missed out on the internship opportunity.

In 2026, Mastercard came back with an SDE-1 opportunity.

This time, I made it through.

7. Overall Experience

Overall, the interview process was a really good learning experience.

What I liked most was that the interviews weren't limited to simply solving standard DSA questions.

The process tested different aspects of a candidate:

• DSA and problem solving

• Data structures

• Programming fundamentals

• Ability to reason under constraints

• Programming-language knowledge

• System-design thinking

• Communication

• Resume/project knowledge

• Behavioral and HR questions

• Ability to handle questions outside your comfort zone

There were moments where I got nervous, especially during the large-file sorting problem. I also couldn't answer the Java

1.equals()

1==

But I tried to think aloud, explain my reasoning, be honest about what I knew, and continue the conversation even when I wasn't sure about something.

And ultimately, that was enough to get through.

8. Final Verdict

🎉 Selected — Mastercard SDE-1

11 candidates were selected, and fortunately, I was one of them.

What makes this experience particularly special to me is that this wasn't my first interaction with Mastercard.

I had already come close in 2025 through Code for Change 2.0, only to miss the internship opportunity after making it to the top 200.

A year later, I got another chance.

This time, I made it through.

Sometimes a missed opportunity really is just another opportunity waiting to come around.

I hope this experience helps anyone preparing for Mastercard or similar SDE roles. If you’re a fellow student and have any questions about the process, preparation, or my experience, feel free to reach out to me on LinkedIn. I’ll be happy to help wherever I can.

LinkedIn: https://www.linkedin.com/in/humanshu-ise/