A–Z of IT Interview Vocabulary: Glossary for Beginners
Starting your IT career? This A–Z glossary breaks down the most common and important terms you’ll encounter during interviews. From acronyms to buzzwords, we've got you covered.
A – API (Application Programming Interface)
A set of rules that allows software programs to communicate with each other. You’ll often be asked how you build or consume APIs.
B – Backend
The server-side logic of a web application, usually built with languages like Java, Python, or Node.js. Interviewers ask about database access, performance, and logic.
C – CI/CD (Continuous Integration / Continuous Deployment)
Automation practices used to integrate and deploy code frequently and reliably. You'll likely be asked about tools like Jenkins, GitHub Actions, or GitLab CI.
D – Docker
A platform used to package applications in containers to make them portable and consistent across environments. Interviewers may ask you how you containerize an app.
E – Exception Handling
A coding mechanism to catch and manage errors gracefully. Be prepared to answer how your code handles failures and avoids crashes.
F – Frontend
The user-facing part of a web app, developed using HTML, CSS, and JavaScript frameworks like React, Angular, or Vue. UI questions often focus on responsiveness and performance.
G – Git
A version control system for tracking changes in code. You’ll be expected to understand branching, commits, and merges.
H – HTTP (HyperText Transfer Protocol)
The foundation of data communication on the web. Know the difference between GET, POST, PUT, DELETE methods and status codes like 200, 404, 500.
I – Inheritance
An Object-Oriented Programming concept where one class can inherit properties and methods from another. A basic OOP interview staple.
J – JSON (JavaScript Object Notation)
A lightweight data-interchange format often used in APIs and frontend/backend communication. Be ready to read and write JSON snippets.
K – Kubernetes
An open-source system for managing containerized applications. Even as a beginner, having a basic idea of orchestration is a plus.
L – Load Balancer
A tool that distributes traffic across multiple servers to ensure no single server is overwhelmed. Frequently discussed in system design interviews.
M – Microservices
A software architecture where functionality is broken into smaller, independent services. Expect questions on how to manage communication and deployment.
N – NullPointerException
A common runtime error in languages like Java that occurs when an object is accessed without initialization. Be ready to debug such errors.
O – OAuth
An authorization framework used to grant limited access to user data. Common in login/authentication questions.
P – Postman
A tool used to test APIs. Interviewers might ask you to demonstrate or describe how you use it to validate endpoints.
Q – Query (SQL)
A command used to fetch or manipulate data in databases. Be prepared to write SELECT, JOIN, GROUP BY, and basic optimization queries.
R – REST (Representational State Transfer)
An architectural style for building APIs. You should know REST principles, status codes, and differences with GraphQL.
S – Scalability
The ability of an application to handle increased load. Interviewers may ask how your code or system scales horizontally or vertically.
T – Thread
A basic unit of execution in programming. Questions often cover concurrency, synchronization, and multithreading in Java or C#.
U – Unit Testing
Testing individual components of a system in isolation. Know tools like JUnit, NUnit, or Jest, and be ready to write or explain simple test cases.
V – Version Control
The practice of tracking and managing changes in code. Git is the most common tool; interviewers may ask about workflow and merge conflicts.
W – WebSocket
A protocol providing full-duplex communication between client and server. Useful in real-time applications like chat or games.
X – XML (eXtensible Markup Language)
Used for data representation, often in older APIs or enterprise systems. You may be asked to parse or transform XML.
Y – YAML
A human-readable configuration format, used in tools like Kubernetes and Docker Compose. Expect basic syntax questions.
Z – Zero Downtime Deployment
A deployment strategy that ensures users experience no service interruption. Commonly discussed in DevOps and cloud interviews.
Final Thoughts
Mastering this vocabulary won’t just help you understand interview questions—it will help you answer them confidently and ask smarter questions back. Don’t memorize definitions alone—apply each concept in projects or mock interviews for maximum impact.