My Juspay Internship cum PPO Experience | SDE (FP-Engineer for Backend [Intern]) (2025)

“It’s not about how fast you get there. It’s about what you learn along the way.” — Me, after the Juspay journey.

When I first came across the Internship cum PPO Opportunity at Juspay Technologies Pvt. Ltd, the role description had me at “concise equation like code using PureScript.” And the icing on the cake? A CTC of ₹27,00,000 😳

So naturally, I threw my name in the hat for the SDE (FP-Engineer for Backend [Intern]) role. This blog is my walkthrough of the entire process — filled with challenges, learning, and some humbling realizations.

About the Role — What Caught My Eye

• Learn to build APIs in PureScript and Presto Backend framework.
• Work with large-scale distributed systems using tech like Kubernetes, NodeJS, Cassandra, AWS, and GCP.
• Collaborate directly with PMs, UX teams, and banks!
• Identify hidden abstractions across payment systems and write clean, reusable code.

Honestly, this role screamed “intellectually intense” and “deep engineering” — so I braced myself.

Round 1: Online DSA Test (22nd March 2025)

Applicants: ~875 Shortlisted: 98

This was the first real gatekeeper. We had to solve 3 DSA questions, mixing up topics like:

• Tree Graphs
• Dynamic Programming
• Matrix manipulation

It wasn’t a cakewalk. The difficulty curve was high, and the questions were different for each candidate. Thankfully, I cleared this round and got shortlisted!

Round 2: Technical MCQs (28th March 2025)

Test Duration: 60 minutes Format: 16 MCQs

• 2 from Physics
• 5 from OS
• 6 from CS fundamentals
• 3 from Math

This round was a true test of breadth and depth. Questions ranged from basic definitions to advanced problem-solving, and it genuinely tested how solid your foundations are. Shortlisted: 82

Intro Call + Hackathon Part A (8th April 2025)

The Intro Call:

A warm-up session with insights about the company, culture, and what lies ahead. Google Meet, nervous faces, and HRs telling us, “This is where the real game begins.”

Hackathon Part A:

• Conducted on HackerEarth (3 hours).
• One legendary question asked every year (Yes, that one 👇):
• GitHub Solution Link
• JobOverflow Thread

Minimum required score: 200/300 Scoring mechanism: 10 sub-tasks, each 30 marks → You need at least 7 passing sub-tasks.

I managed to pass this round too Shortlisted after this round: 49

The Elimination Interview (DSA-based)

This round was the final hurdle before Hackathon Part B — and it came unannounced like a pop quiz. Everyone got a single DSA problem, and our ability to optimize and explain under pressure was under scrutiny.

My Problem:

“Assume you are the manager of a simulation world, where it’s raining. Each raindrop occupies one tile in an N x N matrix. If a drop has adjacent neighbors (only via edges), it merges to form a puddle. You're given a stream of drop placements and later, queries asking whether two drops belong to the same puddle.”

Part 1: You had to maintain the matrix state and dynamically manage merging puddles.

Part 2 (The kicker): Efficiently answer multiple queries like:

• “Do these two coordinates belong to the same puddle?”

I approached it using a DFS traversal — tracked drops and grouped puddles recursively. While this solved the basic problem, the follow-up question asked for optimization.

And that’s where I stumbled.

What they expected:

A Disjoint Set Union (DSU) solution — precisely the kind of efficient structure needed for dynamic connectivity checks.

Unfortunately, I wasn’t well-prepared with DSU at that moment, and that cost me the round.

What’s interesting is — many of my peers got the same question or close variants of it. This seems to be a favorite for gauging both thinking and optimization skills.

What I Learned

1. Graphs + DSU is a deadly combo — be it puddles or people in a network.
2. You should not just solve the problem — you need to optimize it live.
3. Understanding patterns in interview questions gives you a leg up.
4. One failure doesn’t erase your skillset — it reveals what’s next to master.

Final Thoughts

While I didn’t make it to the final PPO offer, this experience was nothing short of amazing. I interacted with brilliant minds, understood how companies like Juspay operate at scale, and learned where I stand in the larger tech landscape.

To anyone preparing for this opportunity — focus on DSA depth, brush up core subjects, and don’t ignore previous year Hackathon problems. Most importantly, don’t get disheartened. Every process is a lesson.

See you on the other side 👨‍💻✨