Paytm / One97 Communications interview process (2026)

Round-by-round breakdown of the Paytm / One97 Communications software engineering interview across 4 levels and 17 rounds: interview mode, sample questions, and worked solutions.

Paytm / One97 Communications salary & ratings · All interview processes

Software Engineer Intern / SDE Intern (PPO-track; on-campus reports cite ~6-month term)

Difficulty: Medium · Timeline: ~1 week · Recommended prep: 4-8 weeks

  1. Round 0: Resume / Eligibility Shortlisting

    Other · N/A (screening) · difficulty 1/5 · elimination round

    Mode of interview: Interview format varies by team

  2. Round 1: Online Coding Assessment (DSA + SQL)

    Assessment · ~60-70 min · difficulty 2/5 · elimination round

    Mode of interview: Online assessment

    Sample question: First Negative Integer in Every Window of Size K — Given an array of integers and a window size k, output the first negative integer in each contiguous window of size k. If a window has no negative integer, output 0 for that window.

  3. Round 2: Technical Interview 1 (Coding + Fundamentals)

    Onsite · ~45-60 min · difficulty 2/5 · elimination round

    Mode of interview: Onsite or virtual onsite interview

    Sample question: LRU Cache — Implement an LRU cache with a fixed capacity supporting get(key) (return value or -1 if absent) and put(key, value), both in O(1). When capacity is exceeded, evict the least-recently-used entry. Read capacity, then a sequence of operations; print each get's result.

  4. Round 3: Technical Interview 2 (Coding + CS Core)

    Onsite · ~45-60 min · difficulty 2/5 · elimination round

    Mode of interview: Onsite or virtual onsite interview

    Sample question: Detect Loop in a Linked List — Given a singly linked list, determine whether it contains a cycle. Output 1 if a loop exists, 0 otherwise. Use Floyd's tortoise-and-hare (O(1) extra space).

  5. Round 4: HR / Behavioral Round

    Behavioral · ~20-30 min · difficulty 1/5

    Mode of interview: Live behavioral interview

SDE-1 (Software Engineer)

Difficulty: Medium · Timeline: ~2-3 weeks · Recommended prep: 4-8 weeks · Cooldown: 6 months

  1. Round 0: Online Assessment (HackerRank)

    Assessment · 60-90 min · difficulty 2/5 · elimination round

    Mode of interview: Online assessment · HackerRank

    Sample question: LRU Cache — Design a Least-Recently-Used cache supporting get(key) and put(key,value) in O(1). On capacity overflow evict the least recently used key. Reads and writes both count as a use.

  2. Round 1: Technical Round 1 (DSA + Fundamentals)

    Phone · ~60 min · difficulty 2/5 · elimination round

    Mode of interview: Remote phone or video interview

    Sample question: Longest Substring Without Repeating Characters — Given a string, return the length of the longest substring that contains no repeating characters.

  3. Round 2: Technical Round 2 (DSA + Core Java / OOP)

    Onsite · ~60 min · difficulty 3/5 · elimination round

    Mode of interview: Onsite or virtual onsite interview

    Sample question: Maximum Subarray (Kadane's Algorithm) — Given an integer array, find the contiguous subarray with the largest sum and return that sum. Paytm often asks a variation (e.g. with constraints or index recovery).

  4. Round 3: Hiring Manager / Managerial (sometimes VP) Round

    Behavioral · ~30-45 min · difficulty 1/5

    Mode of interview: Live behavioral interview

SDE-2 (Senior Software Engineer / SSE)

Difficulty: Hard · Timeline: ~2-4 weeks · Recommended prep: 6-10 weeks · Cooldown: ~6 months

  1. Round 0: Online Assessment (HackerRank) — when applicable

    Assessment · ~90 min · difficulty 3/5 · elimination round

    Mode of interview: Online assessment · HackerRank

    Sample question: Trapping Rain Water — Given n non-negative heights representing an elevation map where each bar width is 1, compute how much water it can trap after raining.

  2. Round 1: Technical Round 1 (DSA + Core Java/Spring/Kafka)

    Phone · ~60 min · difficulty 3/5 · elimination round

    Mode of interview: Remote phone or video interview

    Sample question: Binary Tree Maximum Path Sum — Given a binary tree, return the maximum path sum, where a path is any node sequence connected by parent-child edges (need not pass through the root) and uses each node at most once.

  3. Round 2: Technical Round 2 (Java Deep Dive + LLD / Concurrency + System Design)

    System_design · ~60-75 min · difficulty 4/5 · elimination round

    Mode of interview: Live system design interview

    Sample question: Design a Real-Time Payment / Transaction System — Design Paytm's end-to-end payment flow: user-to-merchant transaction, wallet debit/credit, idempotent request handling (retry with idempotency keys), ACID guarantees on the ledger, a fraud-detection pipeline, and user/merchant notifications. Discuss race conditions and consistency under concurrency.

  4. Round 3: Managerial Round

    Behavioral · ~30-45 min · difficulty 1/5

    Mode of interview: Live behavioral interview

SDE-3 (Lead / Staff Engineer)

Difficulty: Hard · Timeline: ~3-4 weeks · Recommended prep: 8-12 weeks · Cooldown: ~6 months

  1. Round 0: Technical Round 1 (Core Java, Microservices & Kafka)

    Phone · ~60 min · difficulty 3/5 · elimination round

    Mode of interview: Remote phone or video interview

    Sample question: Burst Balloons — Given n balloons with values, bursting balloon i earns nums[left]*nums[i]*nums[right] coins (adjacent boundaries; out-of-range treated as 1). Return the maximum coins obtainable by bursting all balloons in an optimal order.

  2. Round 1: Technical Round 2 (Real-time Transaction Flow + Fraud Detection)

    System_design · ~60-75 min · difficulty 4/5 · elimination round

    Mode of interview: Live system design interview

    Sample question: Design a Seat-Booking / Reservation System (bus/train) with Concurrency — Given a booking UI, design the full backend: search available seats, availability check, seat-blocking/hold, booking confirmation, double-booking prevention under concurrency (optimistic vs pessimistic locking), retries with idempotency keys, and booking history. Discuss consistency and race conditions at scale.

  3. Round 2: System Design Round (Booking / Large-scale)

    System_design · ~60 min · difficulty 4/5 · elimination round

    Mode of interview: Live system design interview

    Sample question: Design Video View-Count & Like-Count / Streaming System — Design a system to count video views and likes at scale (write-heavy counters, eventual consistency, sharding/aggregation) and the supporting video-streaming delivery path (CDN, chunking, adaptive bitrate).

  4. Round 3: Debugging + Architecture Deep Dive / Managerial

    Behavioral · ~45 min · difficulty 3/5

    Mode of interview: Live behavioral interview

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Worked sample solutions (code, design diagrams, and STAR answers) for every round are available in the FAANGPlus app: open interview processes.