Juspay.
Payment orchestration for merchants and banks, including the open-source Hyperswitch router, checkout SDKs, UPI stack and card tokenisation.
its questions lean on
- concurrency and locking
- thread-safe data structures
- payment routing across gateways
- OS and networking fundamentals
- debugging from logs
The rounds, as candidates describe them
- Online assessment and MCQA coding test on trees and graphs, then an MCQ round on aptitude, physics, operating systems and core CS.source ↗
- Hackathon part ASolve a tree-locking problem.source ↗
- Elimination interviewsLive coding by screen share with DSA, puzzles and core CS questions.source ↗
- Hackathon part BA day-long session over Slack making the part-A solution thread-safe and fast, with granular locking.source ↗
- System design and culture fitFinal onsite round.source ↗
Reported by candidates
From public interview write-ups; each links its source.- Design a thread-safe lock/unlock treeLow-level designW05 · DAY 05 · Leader Election and Coordination →W00 · PART 5 · Operating System Concepts for System Design →reported in:LeetCode Discuss · Juspay SDE interview experience, 7 rounds (2026) ↗LeetCode Discuss · Juspay interview experience (2024) ↗LeetCode Discuss · Juspay hackathon interview experience (2023) ↗
- Implement a lock without mutexes, semaphores or atomicsConceptW00 · PART 5 · Operating System Concepts for System Design →reported in:LeetCode Discuss · Juspay Tree of Space hackathon part B discussion (2023) ↗
- Debug a system from its log fileConceptW10 · DAY 02 · Observability →W10 · DAY 05 · Incident Management →reported in:LeetCode Discuss · Juspay Product Solution Engineer, Jan 2026 ↗
- How does OS process scheduling work?ConceptW00 · PART 5 · Operating System Concepts for System Design →reported in:LeetCode Discuss · Juspay 5 of 7 rounds experience (2025) ↗
- Networking fundamentals deep diveConceptW00 · PART 4 · Networking Fundamentals for System Design →reported in:LeetCode Discuss · Juspay SDE, Jul 2023 ↗
Likely, from what they build
Our pick, not a report: questions that fit Juspay's products.- Design a payment router across multiple gatewaysSystem designSQ-18 · Razorpay Payment Gateway →W02 · DAY 03 · Circuit Breakers →W02 · DAY 01 · Timeout Hell →
- Design a Payment SystemSystem designSQ-01 · India's UPI →IP-20 · Design a Payment System →
- Design idempotent payment APIsConceptW02 · DAY 02 · Idempotency in Practice →
- Design webhook delivery with retriesSystem designW02 · DAY 04 · Webhook Delivery System →W03 · DAY 04 · Dead Letters and Poison Pills →
- Design a card tokenisation vaultSystem designW09 · DAY 05 · Security Architecture →SQ-04 · Visa/Mastercard Global Payment Network →
- Design a Rate LimiterSystem designIP-02 · Design a Rate Limiter →W01 · DAY 03 · Rate Limiting at Scale →
Study path
Every lesson the questions above point to, once, in order.
- 01W05 · DAY 05Leader Election and Coordination
- 02W00 · PART 5Operating System Concepts for System Design
- 03W10 · DAY 02Observability
- 04W10 · DAY 05Incident Management
- 05W00 · PART 4Networking Fundamentals for System Design
- 06SQ-18Razorpay Payment Gateway
- 07W02 · DAY 03Circuit Breakers
- 08W02 · DAY 01Timeout Hell
- 09SQ-01India's UPI
- 10IP-20Design a Payment System
- 11W02 · DAY 02Idempotency in Practice
- 12W02 · DAY 04Webhook Delivery System
- 13W03 · DAY 04Dead Letters and Poison Pills
- 14W09 · DAY 05Security Architecture
- 15SQ-04Visa/Mastercard Global Payment Network
- 16IP-02Design a Rate Limiter
- 17W01 · DAY 03Rate Limiting at Scale
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