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Junior Backend to Senior Backend

A staged curriculum that takes a working junior backend engineer to a senior backend interview loop. Strengthens the algorithms and data-structures floor, builds the database and distributed-systems vocabulary senior interviewers expect, climbs through coding difficulty, and finishes with the system-design and behavioral evidence that decides senior offers.

Senior Backend EngineerSenior~60h7 sections30 items
Section 1 of 7

Foundations: Algorithms and Data Structures

Most senior backend loops still open with a coding round. Refresh the patterns first - hash maps, two pointers, binary search, BFS/DFS - before climbing into systems work.

  1. 01MCQAlgorithms questions (30 suggested)Multiple choice category
  2. 02MCQData Structures questions (30 suggested)Multiple choice category
Section 2 of 7

Coding: Easy patterns

Warm-up problems that lock in the core patterns: hash maps, two pointers, simple traversals. If any of these feel uncertain, slow down here - the senior loop assumes these are reflexive.

  1. 01CodeTwo SumCoding · Easy
  2. 02CodeValid ParenthesesCoding · Easy
  3. 03CodeBinary SearchCoding · Easy
  4. 04CodeMerge Two Sorted ListsCoding · Easy
  5. 05CodeBest Time to Buy and Sell StockCoding · Easy
Section 3 of 7

Coding: Medium patterns

Mid-tier coding problems are where most senior loops get decided. Aim to finish each in ~25 minutes with a clean solution and a concrete time/space analysis.

  1. 01CodeLongest Substring Without Repeating CharactersCoding · Medium
  2. 02Code3SumCoding · Medium
  3. 03CodeGroup AnagramsCoding · Medium
  4. 04CodeProduct of Array Except SelfCoding · Medium
  5. 05CodeNumber of IslandsCoding · Medium
  6. 06CodeCourse ScheduleCoding · Medium
  7. 07CodeKth Largest Element in an ArrayCoding · Medium
Section 4 of 7

Coding: Hard patterns

Hard problems test whether you can structure an unfamiliar problem under pressure. You will not always finish - that is fine. Practice the framing, identify the right pattern, and code the cleanest correct version you can.

  1. 01CodeMerge k Sorted ListsCoding · Hard
  2. 02CodeTrapping Rain WaterCoding · Hard
  3. 03CodeLRU CacheCoding · Hard
  4. 04CodeSerialize and Deserialize Binary TreeCoding · Hard
Section 5 of 7

Database fundamentals

Senior backend interviews assume fluency with indexing, transactions, and the trade-offs between SQL and NoSQL. Anchor these before stepping into system design.

  1. 01MCQDatabases questions (25 suggested)Multiple choice category
Section 6 of 7

System Design basics

The bounded designs that show up in mid-to-senior loops. Each walkthrough covers requirements, capacity estimation, architecture, and trade-offs - the structure interviewers grade against.

  1. 01MCQSystem Design questions (25 suggested)Multiple choice category
  2. 02DesignDesign a URL Shortener (bit.ly)System Design · Medium
  3. 03DesignDesign a Rate Limiter (API Throttling)System Design · Medium
  4. 04DesignDesign a Distributed Cache (Memcached / Redis Cluster)System Design · Hard
  5. 05DesignDesign a News Feed (Twitter / Facebook)System Design · Hard
  6. 06DesignDesign a Chat System (WhatsApp / Slack)System Design · Hard
Section 7 of 7

Behavioral: Ownership evidence

Senior backend offers turn on whether you can show ownership, push back when warranted, and learn from incidents. Build STAR answers around these themes before the loop.

  1. 01BehavioralOwnership (Amazon Leadership Principle)Behavioral · Amazon LP
  2. 02BehavioralDive Deep (Amazon Leadership Principle)Behavioral · Amazon LP
  3. 03BehavioralMissed Deadline or Production IncidentBehavioral · General
  4. 04BehavioralLeadership Without AuthorityBehavioral · General
  5. 05BehavioralLearning from FailureBehavioral · Microsoft

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Three role-targeted paths are live: Backend, SRE / DevOps, and ML Engineer. More are on the way - if you have a role you want covered, let us know.

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