50+ Software Developer Interview Questions: Coding, System Design & Behavioral

Software developer interview questions in 2025 span four critical categories that determine your success: coding challenges, system design problems, behavioral scenarios, and technical fundamentals.

Whether you're preparing for FAANG companies or innovative startups, understanding the most frequently asked questions and how to structure compelling answers is essential.

This comprehensive guide breaks down the exact questions you'll encounter, proven answer frameworks, and insider insights from top tech companies. Our complete technical interview guide provides additional preparation strategies to complement these specific question breakdowns.

Technical Coding Interview Questions: Master the Fundamentals

Data structures and algorithms form the backbone of 85% of coding interviews across all major tech companies. Here are the essential question categories you'll encounter:

Array and String Manipulation

These foundational problems test your ability to handle basic data structures efficiently. Common questions include:

Tree and Graph Traversal

Graph and tree problems appear in 60% of technical interviews and test your recursive thinking abilities. Master these patterns:

• Binary Tree Traversal: Practice inorder, preorder, and postorder traversals both recursively and iteratively
• Graph Search Algorithms: Understand when to use BFS vs DFS for different problem types
• Dynamic Programming on Trees: Questions involving path sums, subtree properties, and tree reconstruction

Dynamic Programming Challenges

DP problems separate junior from senior developers. Practice medium-level DP problems focusing on:

• Memoization vs tabulation approaches
• 1D and 2D DP patterns (knapsack, longest common subsequence)
• State space optimization techniques

System Design Interview Questions: Think at Scale

System design questions evaluate your ability to architect large-scale systems and are mandatory for mid-level and senior positions. Here's how to approach them systematically:

Most Asked System Design Questions in 2025

Based on recent interview reports from major tech companies, these questions appear most frequently:

1. Design a Chat Application (WhatsApp/Slack): Focus on real-time messaging, scalability, and message delivery guarantees
2. Design a Social Media Feed (Instagram/Twitter): Emphasize content ranking algorithms and handling millions of users
3. Design a URL Shortener (TinyURL): Demonstrate understanding of encoding, caching, and analytics
4. Design a Video Streaming Platform (YouTube/Netflix): Cover content delivery networks, video encoding, and global distribution

The SCALED Framework for System Design

Use this proven approach to structure your system design responses:

Behavioral Interview Questions: Showcase Your Soft Skills

Behavioral questions assess cultural fit and communication skills, determining whether you can collaborate effectively in team environments. These questions decide 40% of hiring decisions at top tech companies. Mastering proper interview answer structure is crucial for delivering compelling responses.

Master the STAR Method for Every Response

Structure every behavioral response using this proven framework:

• Situation (20%): Set the context briefly without unnecessary details
• Task (15%): Explain your specific responsibility or challenge
• Action (50%): Detail the steps you took and decision-making process
• Result (15%): Quantify the outcome and lessons learned

Most Asked Behavioral Questions by Category

Leadership and Influence Questions:

• "Tell me about a time you convinced someone to change their mind"
• "Describe a situation where you had to lead without formal authority"
• "How did you handle a team member who wasn't performing well?"

Problem-Solving and Conflict Resolution:

• "Tell me about a challenging bug you debugged"
• "Describe a time you disagreed with a technical decision"
• "How do you tackle challenges when you don't know the solution immediately?"

Learning and Adaptability:

• "Tell me about a project where you had to learn new technology quickly"
• "Describe a time you received difficult feedback and how you responded"
• "How do you stay updated with new technologies and industry trends?"

Programming Language-Specific Questions

Most interviews include language-specific technical questions. Practice with our AI-powered interview simulator to get comfortable with these question types across different programming languages.

JavaScript Interview Questions

• Explain closures and provide a practical example
• What's the difference between var, let, and const?
• How does the event loop work in Node.js?
• Implement a debounce function from scratch

Python Interview Questions

• Explain the difference between lists and tuples
• How does Python's Global Interpreter Lock (GIL) work?
• What are decorators and when would you use them?
• Implement a context manager using both class and function approaches

Java Interview Questions

• Explain the difference between ArrayList and LinkedList
• How does garbage collection work in Java?
• What are the differences between abstract classes and interfaces?
• Implement a thread-safe singleton pattern

FAANG Interview Questions: What to Expect

FAANG companies (Facebook, Amazon, Apple, Netflix, Google) are known for asking specific types of questions that test both technical depth and problem-solving creativity. Recent FAANG interview reports reveal these commonly asked question patterns:

Google's Favorite Questions

• Algorithm focus: Graph traversal problems, dynamic programming variations
• System design: "Design Google Search" with emphasis on crawling and indexing
• Behavioral: "Tell me about a time you convinced someone to change their mind"

Amazon's Leadership Principle Questions

• Customer obsession: "Tell me about a time you went above and beyond for a customer"
• Ownership: "Describe a project you owned from start to finish"
• Technical depth: Focus on distributed systems and scalability challenges

Common Technical Questions Across All Levels

Beyond coding challenges, interviewers frequently ask conceptual questions to gauge your understanding of software development principles:

Computer Science Fundamentals

• "Explain the difference between a stack and a queue" - Tests basic data structure knowledge
• "What is time complexity and why does it matter?" - Assesses algorithm analysis skills
• "Describe how hash tables work internally" - Evaluates understanding of core data structures
• "Explain the difference between breadth-first and depth-first search" - Tests graph algorithm knowledge

Software Engineering Concepts

• "What are the principles of object-oriented programming?" - Tests OOP fundamentals
• "Explain the difference between SQL and NoSQL databases" - Assesses database knowledge
• "What is the software development lifecycle?" - Tests process understanding
• "Describe different testing methodologies" - Evaluates quality assurance knowledge

Real Coding Questions Asked at Top Companies

Here are actual coding questions reported by candidates at major tech companies, organized by difficulty and company frequency:

Entry-Level Questions (0-2 years experience)

Mid-Level Questions (2-5 years experience)

Frequently Asked Questions About Interview Questions

What types of coding questions do FAANG companies ask most frequently?

FAANG companies focus heavily on graph algorithms, dynamic programming, and tree traversal problems. This curated collection of FAANG interview questions shows that array manipulation and string processing account for 40% of coding questions, while system design questions emphasize scalability and distributed systems.

How should I structure my answers to behavioral interview questions?

Always use the STAR method (Situation, Task, Action, Result) to structure behavioral responses. Focus 50% of your answer on the specific actions you took, and always quantify results when possible. Practice explaining technical decisions to non-technical stakeholders.

What's the difference between system design questions for junior vs senior developers?

Junior developers typically get simplified system design questions like "Design a URL shortener," focusing on basic components. Senior developers face complex problems like "Design Instagram's architecture" with deep dives into scalability, data consistency, and performance optimization.

Which programming languages are most commonly tested in software developer interviews?

Python dominates with 60% of coding interviews due to its clean syntax, followed by Java (25%) and JavaScript (15%). Choose the language you're most comfortable with, but be prepared to explain language-specific concepts like Python's GIL or JavaScript's event loop.

What are the most challenging types of interview questions candidates struggle with?

Candidates report the highest difficulty with dynamic programming questions and open-ended system design problems. These require pattern recognition and the ability to break complex problems into smaller, manageable components.

How specific should my answers be when explaining technical concepts?

Balance technical depth with clarity. For algorithm questions, explain time and space complexity. For system design, discuss specific technologies but focus on why you chose them. Always start with the high-level approach before diving into implementation details.