Top 50 Backend Interview Questions Handbook

Top 50 Backend Interview Questions Every Developer Should Know

This 5-page handbook covers essential backend interview topics, including fundamentals, system design, and production-ready architecture.

Key Topics Covered:

• REST APIs & HTTP Methods: Understanding how to design and interact with RESTful services.
• Authentication:
  • JWT (JSON Web Tokens): Stateless authentication mechanism.
  • OAuth: Authorization framework.
  • Sessions: Stateful authentication using server-side sessions.
• SQL & Database Concepts:
  • Indexing: Clustered vs. Non-Clustered indexes for performance.
  • Transactions: Ensuring data integrity.
  • Query Optimization: Techniques to improve database query speed.
• System Design & Scalability: Principles for building large-scale applications.
• Caching: Using Redis for efficient data retrieval.
• Load Balancers: Distributing traffic across servers.
• Microservices & API Gateway: Architectural patterns for distributed systems.
• SOLID Principles & Design Patterns: Best practices for object-oriented design.
• Docker & CI/CD Basics: Containerization and continuous integration/delivery.
• Project Architecture Interview Tips: Guidance on discussing system architecture.

Content Features:

• Concise explanations
• Comparison tables
• Diagrams
• Production tips
• Interview-focused insights

Call to Action:

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• Comment "BACKEND" to receive the complete PDF notes.

Post Details:

• Author: @codewith.z_ (TechFreak)
• Posted: July 17, 2026
• Likes: 1758
• Comments: 615
• URL: https://www.instagram.com/p/Da5V453AV4U/

Specific Content from Pages:

• Page 2 (Authentication): Differentiates between Authentication (verifying identity) and Authorization (checking permissions). Discusses JWT, Sessions (stateful vs. stateless), OAuth, and their storage mechanisms (local storage, server sessions). Mentions HTTPS, TLS/SSL, CORS, CSRF, and Rate Limiting.
• Page 3 (Database & SQL): Explains Clustered vs. Non-Clustered indexes, ACID properties (Atomicity, Consistency, Isolation, Durability), different types of SQL JOINs (INNER, LEFT, RIGHT, FULL), and the purpose of Stored Procedures. Covers SQL LIMIT and data clauses.

Hashtags: #BackendDeveloper #BackendInterview #SoftwareEngineer #SystemDesign #RESTAPI