Interview preparation for full-stack developers

Full Stack Interview Guru

Interview Tomorrow? Start Here.

316 interview questions across 13 topics, from Core Java and the JVM to REST APIs, SQL, AWS and system design. Answers are written for the interview room: a short answer you can say out loud, the reasoning behind it, code where it helps, and the follow-ups that usually come next.

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  1. What is a HashMap?

    Core Java · Collections    Easy

  2. What is the Stream API and how is it different from a loop?

    Java 8+ · Stream API    Medium

  3. What is a JWT and how does it work?

    REST APIs · Auth    Medium

  4. Solve Two Sum — return indices of two numbers adding to a target.

    Coding Challenges · HashMaps    Easy

  5. Which HTTP methods are idempotent and why does it matter?

    REST APIs · Idempotency    Medium

  6. What is AWS Lambda and when would you use it?

    AWS · Lambda    Medium

  7. How does the DynamoDB partition key affect performance, and what is a hot partition?

    AWS · DynamoDB    Medium

Learning paths

Every topic, arranged so each one builds on the last. Follow a track from its first question, or jump straight to the topic your interview is about.

All topics with details →

Java & the JVM

Language fundamentals and collections first, then modern Java, concurrency, and what happens inside the JVM.

Start withWhat is a HashMap?

  1. Core Java

    29 questions

  2. Java Collections

    23 questions

  3. Java 8+

    10 questions

  4. Multithreading

    30 questions

  5. JVM

    26 questions

  6. Advanced Java

    28 questions

APIs & distributed systems

How services talk to each other: HTTP semantics and payloads, then service boundaries, and finally designing for scale.

Start withExplain the main HTTP status code families.

  1. REST APIs

    24 questions

  2. JSON

    26 questions

  3. Microservices

    20 questions

  4. System Design

    21 questions

Data & cloud

Relational data and query performance, then the core AWS building blocks.

Start withExplain INNER JOIN vs LEFT JOIN.

  1. SQL

    22 questions

  2. AWS

    22 questions

Python

Core data types and idioms, then functions, OOP, generators, and the GIL.

Start withWhat is the difference between a list and a tuple in Python?

  1. Python

    27 questions

Beyond the questions

Prep the whole picture — your machine, your path, your reality.

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