SOAP vs REST vs GraphQL vs RPC

Visualizing SQL Queries

Note: The actual execution sequence may differ from this mental model due to optimization strategies employed by the query optimizer.

SQL Question:

What does this query return for a NULL score?

What is API Gateway?

✅ 50 Must-Know Web Development Concepts for Interviews 🌐💼

📍 HTML Basics 
1. What is HTML? 
2. Semantic tags (article, section, nav) 
3. Forms and input types 
4. HTML5 features 
5. SEO-friendly structure 

📍 CSS Fundamentals 
6. CSS selectors & specificity 
7. Box model 
8. Flexbox 
9. Grid layout 
10. Media queries for responsive design 

📍 JavaScript Essentials
11. let vs const vs var 
12. Data types & type coercion 
13. DOM Manipulation 
14. Event handling 
15. Arrow functions 

📍 Advanced JavaScript 
16. Closures 
17. Hoisting 
18. Callbacks vs Promises 
19. async/await 
20. ES6+ features 

📍 Frontend Frameworks
21. React: props, state, hooks 
22. Vue: directives, computed properties 
23. Angular: components, services 
24. Component lifecycle 
25. Conditional rendering 

📍 Backend Basics
26. Node.js fundamentals 
27. Express.js routing 
28. Middleware functions 
29. REST API creation 
30. Error handling 

📍 Databases 
31. SQL vs NoSQL 
32. MongoDB basics 
33. CRUD operations 
34. Indexes & performance 
35. Data relationships 

📍 Authentication & Security 
36. Cookies vs LocalStorage 
37. JWT (JSON Web Token) 
38. HTTPS & SSL 
39. CORS 
40. XSS & CSRF protection 

📍 APIs & Web Services
41. REST vs GraphQL 
42. Fetch API 
43. Axios basics 
44. Status codes 
45. JSON handling 

📍 DevOps & Tools 
46. Git basics & GitHub 
47. CI/CD pipelines 
48. Docker (basics) 
49. Deployment (Netlify, Vercel, Heroku) 
50. Environment variables (.env)

💬 Tap ❤️ for more!

✅ HTML Basics – Interview Questions & Answers 📄

1️⃣ What is HTML?
Answer: HTML (HyperText Markup Language) is the standard language used to structure content on the web. It defines elements like headings, paragraphs, links, images, and forms using tags.

2️⃣ What are semantic tags in HTML?
Answer: Semantic tags clearly describe their meaning in the context of the page. Examples:
- <article> – for self-contained content
- <section> – for grouped content
- <nav> – for navigation links
They improve accessibility and SEO.

3️⃣ What are forms and input types in HTML?
Answer: Forms collect user input. Common input types include:
- text, email, password, checkbox, radio, submit
Example:

<form>
  <input type="email" placeholder="Enter your email" />
</form>

4️⃣ What are key features of HTML5?
Answer:
- New semantic tags (<header>, <footer>, <main>)
- Native audio/video support (<audio>, <video>)
- Local storage & session storage
- Canvas for graphics
- Geolocation API

5️⃣ How do you create an SEO-friendly HTML structure?
Answer:
- Use semantic tags
- Include proper heading hierarchy (<h1> to <h6>)
- Add alt attributes to images
- Use denoscriptive noscripts and meta tags
- Ensure fast loading and mobile responsiveness

💬 Double Tap ❤️ For More

✅ CSS Fundamentals – Interview Questions & Answers 🎨🧠

1️⃣ What is the Box Model in CSS?
The box model describes how elements are rendered: 
Content -> Padding -> Border -> Margin
It affects spacing and layout.

2️⃣ What’s the difference between ID and Class selectors?
- #id: Unique, used once. 
- .class: Reusable across multiple elements. 
Example: 

#header { color: red; }  
.card { padding: 10px; }

3️⃣ How does CSS Specificity work? 
Specificity decides which styles are applied when multiple rules target the same element. 
Hierarchy: 
Inline > ID > Class > Element 
Example: 

<p id="one" class="two">Text</p>

#one has higher specificity than .two.

4️⃣ What is Flexbox?
A layout model for 1D alignment (row or column). 
Key properties: 
- display: flex
- justify-content, align-items,
flex-wrap

5️⃣ Difference between Flexbox and Grid?
- Flexbox: 1D layout (row/column). 
- Grid: 2D layout (rows & columns). 
Use Grid when layout needs both directions.

6️⃣ What are Media Queries? 
Used to create responsive designs based on screen size/device. 
Example: 

@media (max-width: 600px) {
  body { font-size: 14px; }
}

7️⃣ How do you center a div using Flexbox? 

.container {
  display: flex;
  justify-content: center;
  align-items: center;
}

8️⃣ What is the difference between position: relative and absolute?
- relative: positions relative to itself. 
- absolute: positions relative to the nearest positioned ancestor.

9️⃣ Explain z-index in CSS. 
Controls stacking order of elements. Higher z-index = appears on top.

🔟 How can you optimize CSS performance? 
- Minify files 
- Use shorthand properties 
- Combine selectors 
- Avoid deep nesting 
- Use external stylesheets

💬 Double Tap ❤️ For More

✅ JavaScript Essentials – Interview Questions with Answers🧠💻 

1️⃣ Q: What is the difference between let, const, and var?
A: 
- var: Function-scoped, hoisted, can be redeclared. 
- let: Block-scoped, not hoisted like var, can't be redeclared in same scope. 
- const: Block-scoped, must be assigned at declaration, cannot be reassigned.

2️⃣ Q: What are JavaScript data types? 
A:
- Primitive types: string, number, boolean, null, undefined, symbol, bigint 
- Non-primitive: object, array, function 
Type coercion: JS automatically converts between types in operations ('5' + 2 → '52')

3️⃣ Q: How does DOM Manipulation work in JS?
A:
The DOM (Document Object Model) represents the HTML structure. JS can access and change elements using: 
- document.getElementById() 
- document.querySelector() 
- element.innerText, element.innerHTML, element.style etc.

4️⃣ Q: What is event handling in JavaScript?
A: 
It allows reacting to user actions like clicks or key presses. 
Example: 

document.getElementById("btn").addEventListener("click", () => {
  alert("Button clicked!");
});

5️⃣ Q: What are arrow functions?
A:
A shorter syntax for functions introduced in ES6. 

const add = (a, b) => a + b;

💬 Double Tap ❤️ For More

✅ Advanced JavaScript Interview Questions with Answers 💼🧠

1. What is a closure in JavaScript?
A *closure* is a function that has access to its outer function's variables, even after the outer function has returned.

function outer() {
  let count = 0;
  return function inner() {
    count++;
    console.log(count);
  }
}
const counter = outer();
counter(); // 1
counter(); // 2

2. Explain event delegation.
Event delegation is a technique where you attach a single event listener to a parent element to handle events on its child elements using event.target.

3. What is the difference between == and ===? 
- == checks for value equality (type coercion allowed). 
- === checks for both value and type (strict equality). 

'5' == 5   // true  
'5' === 5  // false

4. What is the "this" keyword?
this refers to the object that is executing the current function. In arrow functions, this is lexically bound (based on where it's defined).

5. What are Promises? 
Promises handle asynchronous operations. They have 3 states: *pending, resolved, rejected*.

const p = new Promise((resolve, reject) => {
  resolve("Success");
});
p.then(console.log);

6. Explain async/await.
Syntactic sugar over Promises for better readability in async code.

async function fetchData() {
  const res = await fetch(url);
  const data = await res.json();
}

7. What is hoisting?
Variables and function declarations are moved to the top of their scope before code execution.

console.log(a); // undefined
var a = 5;

8. What are arrow functions and how do they differ? 
Arrow functions are shorter and do not have their own this, arguments, or super.

const add = (a, b) => a + b;

9. What is the event loop?
The event loop handles asynchronous callbacks and ensures non-blocking behavior in JS by placing them in the task queue after the call stack is clear.

10. What are IIFEs (Immediately Invoked Function Expressions)?
Functions that run as soon as they are defined.

(function() {
  console.log("Runs immediately");
})();

💬 Double Tap ❤️ For More

OnSpace Mobile App builder: Build AI Apps in minutes

With OnSpace, you can build website or AI Mobile Apps by chatting with AI, and publish to PlayStore or AppStore.

🔥 What will you get:
• 🤖 Create app or website by chatting with AI;
• 🧠 Integrate with Any top AI power just by giving order (like Sora2, Nanobanan Pro & Gemini 3 Pro);
• 📦 Download APK,AAB file, publish to AppStore.
• 💳 Add payments and monetize like in-app-purchase and Stripe.
• 🔐 Functional login & signup.
• 🗄 Database + dashboard in minutes.
• 🎥 Full tutorial on YouTube and within 1 day customer service

🌐 Visit website:
👉 https://www.onspace.ai/?via=tg_bigdata

📲 Or Download app:
👉 https://onspace.onelink.me/za8S/h1jb6sb9?c=bigdata

✅  Frontend Frameworks Interview Q&A – Part 1 🌐💼

1️⃣ What are props in React?
Answer: Props (short for properties) are used to pass data from parent to child components. They are read-only and help make components reusable.

2️⃣ What is state in React?
Answer: State is a built-in object used to store dynamic data that affects how the component renders. Unlike props, state can be changed within the component.

3️⃣ What are React hooks?
*Answer:* Hooks like useState, useEffect, and useContext let you use state and lifecycle features in functional components without writing class components.

4️⃣ What are directives in Vue.js?
Answer: Directives are special tokens in Vue templates that apply reactive behavior to the DOM. Examples include v-if, v-for, and v-bind.

5️⃣ What are computed properties in Vue?
Answer: Computed properties are cached based on their dependencies and only re-evaluate when those dependencies change — great for performance and cleaner templates.

6️⃣ What is a component in Angular?
Answer: A component is the basic building block of Angular apps. It includes a template, class, and metadata that define its behavior and appearance.

7️⃣ What are services in Angular?
Answer: Services are used to share data and logic across components. They’re typically injected using Angular’s dependency injection system.

8️⃣ What is conditional rendering?
Answer: Conditional rendering means showing or hiding UI elements based on conditions. In React, you can use ternary operators or logical && to do this.

9️⃣ What is the component lifecycle in React?
*Answer:* Lifecycle methods like componentDidMount, componentDidUpdate, and componentWillUnmount manage side effects and updates in class components. In functional components, use useEffect.

🔟 How do frameworks improve frontend development?
*Answer:* They offer structure, reusable components, state management, and better performance — making development faster, scalable, and more maintainable.

💬 Double Tap ❤️ For More

✅ Frontend Frameworks Interview Q&A – Part 2 🌐💼 

1️⃣ What is Virtual DOM in React?
Answer:
The Virtual DOM is a lightweight copy of the real DOM. React updates it first, calculates the difference (diffing), and then efficiently updates only what changed in the actual DOM.

2️⃣ Explain data binding in Angular.
Answer: 
Angular supports one-way, two-way ([(ngModel)]), and event binding to sync data between the component and the view.

3️⃣ What is JSX in React?
Answer:
JSX stands for JavaScript XML. It allows you to write HTML-like syntax inside JavaScript, which is compiled to React’s createElement() calls.

4️⃣ What are slots in Vue.js?
Answer: 
Slots allow you to pass template content from parent to child components, making components more flexible and reusable.

5️⃣ What is lazy loading in Angular or React? 
Answer: 
Lazy loading is a performance optimization technique that loads components or modules only when needed, reducing initial load time.

6️⃣ What are fragments in React?
Answer:
<React.Fragment> or <> lets you group multiple elements without adding extra nodes to the DOM.

7️⃣ How do you lift state up in React? 
Answer:
By moving the shared state to the closest common ancestor of the components that need it, and passing it down via props.

8️⃣ What is a watch property in Vue?
Answer:
watch allows you to perform actions when data changes — useful for async operations or side effects.

9️⃣ What is dependency injection in Angular?
Answer:
A design pattern where Angular provides objects (like services) to components, reducing tight coupling and improving testability.

🔟 What is server-side rendering (SSR)?
Answer:
SSR renders pages on the server, not the browser. It improves SEO and load times. Examples: Next.js (React), Nuxt.js (Vue), Angular Universal.

💬 Tap ❤️ for more!

✅ Backend Basics Interview Questions – Part 1 (Node.js)🧠💻

📍 1. What is Node.js?
A: Node.js is a runtime environment that lets you run JavaScript on the server side. It uses Google’s V8 engine and is designed for building scalable network applications.

📍 2. How is Node.js different from traditional server-side platforms?
A: Unlike PHP or Java, Node.js is event-driven and non-blocking. This makes it lightweight and efficient for I/O-heavy operations like APIs and real-time apps.

📍 3. What is the role of the package.json file?
A: It stores metadata about your project (name, version, noscripts) and dependencies. It’s essential for managing and sharing Node.js projects.

📍 4. What are CommonJS modules in Node.js? 
A: Node uses CommonJS to handle modules. You use require() to import and module.exports to export code between files.

📍 5. What is the Event Loop in Node.js?
A: It allows Node.js to handle many connections asynchronously without blocking. It’s the heart of Node’s non-blocking architecture.

📍 6. What is middleware in Node.js (Express)? 
A: Middleware functions process requests before sending a response. They can be used for logging, auth, validation, etc.

📍 7. What is the difference between process.nextTick(), setTimeout(), and setImmediate()? 
A: 
- process.nextTick() runs after the current operation, before the next event loop. 
- setTimeout() runs after a minimum delay. 
- setImmediate() runs on the next cycle of the event loop.

📍 8. What is a callback function in Node.js?
A: A function passed as an argument to another function, executed after an async task finishes. It’s the core of async programming in Node.

📍 9. What are Streams in Node.js?
A: Streams let you read/write data piece-by-piece (chunks), great for handling large files. Types: Readable, Writable, Duplex, Transform.

📍 10. What is the difference between require and import?
A:
- require is CommonJS (used in Node.js by default). 
- import is ES6 module syntax (used with "type": "module" in package.json).

💬 Tap ❤️ for more!

✅ Backend Basics Interview Questions – Part 2 (Express.js Routing) 🚀🧠

📍 1. What is Routing in Express.js?
A: Routing defines how your application responds to client requests (GET, POST, etc.) to specific endpoints (URLs).

📍 2. Basic Route Syntax

app.get('/home', (req, res) => {
  res.send('Welcome Home');
});

📍3. Route Methods 
- app.get() – Read data 
- app.post() – Create data 
- app.put() – Update data 
- app.delete() – Delete data 

📍 4. Route Parameters

app.get('/user/:id', (req, res) => {
  res.send(req.params.id);
});

📍 5. Query Parameters 

app.get('/search', (req, res) => {
  res.send(req.query.keyword);
});

📍 6. Route Chaining

app.route('/product')
  .get(getHandler)
  .post(postHandler)
  .put(putHandler);

📍 7. Router Middleware

const router = express.Router();
router.get('/about', (req, res) => res.send('About Page'));
app.use('/info', router);  // URL: /info/about

📍 8. Error Handling Route

app.use((req, res) => {
  res.status(404).send('Page Not Found');
});

💡 Pro Tip: Always place dynamic routes after static ones to avoid conflicts.

💬 Tap ❤️ if this helped you!

✅ Backend Basics Interview Questions – Part 3 (Express.js Middleware) 🚀🧠

📍 1. What is Middleware in Express.js?
A: Middleware are functions that execute during the request-response cycle. They can modify req/res, execute code, or end the request.

📍 2. Types of Middleware 
- Application-level: Applied to all routes or specific routes 
- Router-level: Applied to router instances 
- Built-in: e.g., express.json(), express.static() 
- Third-party: e.g., cors, morgan, helmet

📍 3. Example – Logging Middleware 

app.use((req, res, next) => {
  console.log(`req.method{req.url}`);
  next(); // Pass to next middleware/route
});

📍 4. Built-in Middleware

app.use(express.json()); // Parses JSON body
app.use(express.urlencoded({ extended: true })); // Parses URL-encoded body

📍 5. Router-level Middleware

const router = express.Router();
router.use((req, res, next) => {
  console.log('Router Middleware Active');
  next();
});

📍 6. Error-handling Middleware 

app.use((err, req, res, next) => {
  console.error(err.stack);
  res.status(500).send('Something broke!');
});

📍 7. Chaining Middleware

app.get('/profile', authMiddleware, logMiddleware, (req, res) => {
  res.send('User Profile');
});

💡 Pro Tip: Middleware order matters — always place error-handling middleware last.

💬 Tap ❤️ for more!

✅ Backend Basics Interview Questions – Part 4 (REST API) 🚀💻 

📍 1. What is a REST API?
A: REST (Representational State Transfer) APIs allow clients to interact with server resources using HTTP methods like GET, POST, PUT, DELETE.

📍 2. Difference Between REST & SOAP
- REST uses HTTP, is lightweight, and supports JSON/XML. 
- SOAP is protocol-based, heavier, uses XML, and has strict standards.

📍 3. HTTP Methods
- GET → Read data 
- POST → Create data 
- PUT → Update data 
- DELETE → Delete data 
- PATCH → Partial update 

📍 4. Example – Creating a GET Route

app.get('/users', (req, res) => {
  res.send(users); // Return all users
});

📍 5. Example – POST Route 

app.post('/users', (req, res) => {
  const newUser = req.body;
  users.push(newUser);
  res.status(201).send(newUser);
});

📍 6. Route Parameters & Query Parameters 

app.get('/users/:id', (req, res) => {
  res.send(users.find(u => u.id == req.params.id));
});
app.get('/search', (req, res) => {
  res.send(users.filter(u => u.name.includes(req.query.name)));
});

📍 7. Status Codes
- 200 → OK 
- 201 → Created 
- 400 → Bad Request 
- 404 → Not Found 
- 500 → Server Error 

📍 8. Best Practices
- Validate request data
- Handle errors properly 
- Use consistent endpoint naming 
- Keep routes modular using express.Router() 

💬 Double Tap ❤️ for more!

✅ Backend Basics Interview Questions – Part 5 (Error Handling) 🚀💻 

📍 1. What is Error Handling? 
A: Error handling is the process of catching and responding to errors that occur during request processing, ensuring the server doesn’t crash and clients get meaningful messages. 

📍 2. Built-in Error Handling
- Express automatically catches errors in synchronous routes. 
- Example: 

app.get('/error', (req, res) => {
  throw new Error('Something went wrong!');
});

📍 3. Custom Error-handling Middleware 
- Middleware with 4 parameters (err, req, res, next) handles errors globally. 

app.use((err, req, res, next) => {
  console.error(err.stack);
  res.status(500).send({ message: err.message });
});

📍 4. Try-Catch in Async Functions
- Async route handlers need try-catch to handle errors. 

app.get('/async', async (req, res, next) => {
  try {
    const data = await getData();
    res.send(data);
  } catch (err) {
    next(err);
  }
});

📍 5. Sending Proper Status Codes 
- 400 → Bad Request 
- 401 → Unauthorized 
- 403 → Forbidden 
- 404 → Not Found 
- 500 → Internal Server Error 

📍 6. Error Logging
- Use console.error() or logging libraries like winston or morgan for debugging.

📍 7. Best Practices
- Keep error messages user-friendly. 
- Don’t expose stack traces in production. 
- Centralize error handling. 
- Validate inputs to prevent errors early. 

💬 Tap ❤️ for more!

✅ Databases Interview Questions & Answers 💾💡 

1️⃣ What is a Database? 
A: A structured collection of data stored electronically. Examples: MySQL, MongoDB, PostgreSQL. 

2️⃣ Difference between SQL and NoSQL
- SQL: Relational, structured tables, uses schemas, supports ACID transactions. 
- NoSQL: Non-relational, flexible schema, document/graph/column storage, scalable. 

3️⃣ What is a Primary Key?
A: Unique identifier for a record in a table. Example: id column in Users table. 

4️⃣ What is a Foreign Key? 
A: A field in one table that refers to the primary key of another table to maintain relationships. 

5️⃣ CRUD Operations
- Create: INSERT INTO table_name ... 
- Read: SELECT * FROM table_name ... 
- Update: UPDATE table_name SET ... WHERE ... 
- Delete: DELETE FROM table_name WHERE ... 

6️⃣ What is Indexing?
A: A performance optimization technique to speed up data retrieval. Types: B-Tree, Hash indexes. 

7️⃣ What is Normalization?
A: Process of organizing tables to reduce redundancy and improve data integrity. Forms: 1NF, 2NF, 3NF, BCNF. 

8️⃣ What is Denormalization?
A: Combining tables or duplicating data to improve read performance at the cost of redundancy. 

9️⃣ ACID Properties
- Atomicity: All or nothing transaction 
- Consistency: Database remains valid 
- Isolation: Transactions don’t interfere 
- Durability: Committed changes persist 

🔟 Difference between JOIN types
- INNER JOIN: Only matching rows 
- LEFT JOIN: All left + matching right rows 
- RIGHT JOIN: All right + matching left rows 
- FULL OUTER JOIN:  All rows from both tables 

1️⃣1️⃣ What is a NoSQL Database?
A: Database designed for large-scale, unstructured, or semi-structured data. Types: Document (MongoDB), Key-Value (Redis), Column (Cassandra), Graph (Neo4j). 

1️⃣2️⃣ What is a Transaction? 
A: A set of SQL operations executed as a single unit of work. Either all succeed or all fail. 

1️⃣3️⃣ Difference between DELETE and TRUNCATE
- DELETE: Row-by-row, can use WHERE, slower, logs each row. 
- TRUNCATE: Removes all rows, faster, cannot use WHERE, resets auto-increment. 

1️⃣4️⃣ What is a View?
A: A virtual table representing a stored query. Useful for abstraction, security, and complex queries. 

1️⃣5️⃣ Difference between SQL and ORM
- SQL: Direct queries to DB
- ORM: Object-Relational Mapping, allows interacting with DB using programming language objects (e.g., Sequelize, SQLAlchemy) 

💬 Tap ❤️ if you found this useful!

✅ Authentication & Security – Web Development Interview Questions & Answers 🔐🛡️

1️⃣ What is the difference between Authentication and Authorization? 
Answer: 
- Authentication verifies who the user is (e.g., login). 
- Authorization controls what the user can access (e.g., admin vs user access).

2️⃣ What is JWT (JSON Web Token)?
Answer:
A compact token used for stateless authentication. It contains a header, payload (user info), and signature to verify data integrity.

3️⃣ How is JWT more secure than traditional sessions?
Answer:
JWTs are stored on the client-side and signed with a secret. Unlike sessions, they don’t require server-side storage, making them scalable and tamper-evident.

4️⃣ What's the difference between Cookies and LocalStorage?
Answer: 
- Cookies: Automatically sent with each HTTP request, smaller in size, can be HttpOnly. 
- LocalStorage: Larger, persists longer, not sent with requests (manual access only).

5️⃣ What is CORS? Why is it important?
Answer:
CORS (Cross-Origin Resource Sharing) is a browser mechanism that restricts requests from different origins. It protects against unwanted cross-site access.

6️⃣ What is CSRF and how do you prevent it?
Answer:
CSRF (Cross-Site Request Forgery) tricks a logged-in user into submitting unwanted actions. 
Prevention: Use CSRF tokens, SameSite cookies, and avoid storing sensitive data in localStorage.

7️⃣ What is XSS and how do you prevent it? 
Answer: 
XSS (Cross-Site Scripting) injects malicious noscripts into web pages. 
Prevention:  Escape user input, use Content Security Policy (CSP), and sanitize HTML.

8️⃣ What is HTTPS and why is it critical?
Answer: 
HTTPS encrypts data using SSL/TLS. It ensures data privacy, integrity, and trust between client and server.

9️⃣ How do you implement password security in web apps? 
Answer: 
- Store hashed passwords using bcrypt or Argon2 
- Use salting 
- Enforce strong password rules 
- Implement rate-limiting on login attempts 

🔟 What is OAuth?
Answer: 
OAuth is an authorization protocol that allows users to grant access to third-party apps without sharing credentials (e.g., login with Google/Facebook).

💬 Tap ❤️ if you found this useful!

✅ API & Web Services – Web Development Interview Q&A 🌐💬 

1️⃣ What is an API?
Answer:
API (Application Programming Interface) allows communication between two software systems. It defines how requests and responses should be formatted.

2️⃣ REST vs SOAP – What's the difference?
Answer: 
- REST: Lightweight, uses HTTP, supports JSON/XML 
- SOAP: Protocol-based, strict standards, uses XML 
REST is more common for modern web services.

3️⃣ What is RESTful API? 
Answer: 
An API that follows REST principles: 
- Uses HTTP methods (GET, POST, PUT, DELETE) 
- Stateless 
- Has structured endpoints 
- Supports caching

4️⃣ What are HTTP status codes?
Answer: 
Codes returned in response: 
- 200: OK 
- 201: Created 
- 400: Bad Request 
- 401: Unauthorized 
- 403: Forbidden 
- 404: Not Found 
- 500: Server Error

5️⃣ What is GraphQL?
Answer: 
A query language for APIs by Facebook. 
- Client defines the structure of the response 
- Single endpoint 
- Reduces over-fetching and under-fetching of data

6️⃣ What is CORS?
Answer:
Cross-Origin Resource Sharing – A security feature in browsers that blocks requests from other origins unless explicitly allowed by the server.

7️⃣ What is rate limiting?
Answer:
Limits the number of API requests a user/client can make within a time frame to prevent abuse.

8️⃣ What is an API key and how is it used?
Answer:
An API key is a token used to authenticate and authorize access to APIs. It’s passed in headers or query strings.

9️⃣ Difference between PUT and PATCH?
Answer:
- PUT: Replaces the entire resource 
- PATCH: Updates only specified fields

🔟 What is a webhook?
Answer:
A way for servers to send data automatically to other services (e.g., when an event happens). It’s push-based, unlike APIs which are pull-based.

💬 Tap ❤️ if you found this useful!

✅ Git & GitHub Interview Questions & Answers 🧑‍💻🌐 

1️⃣ What is Git? 
A: Git is a distributed version control system to track changes in source code during development.

2️⃣ What is GitHub? 
A: GitHub is a cloud-based platform that hosts Git repositories and supports collaboration, issue tracking, and CI/CD.

3️⃣ Git vs GitHub
- Git: Version control tool (local) 
- GitHub: Hosting service for Git repositories (cloud-based) 

4️⃣ What is a Repository (Repo)?
A: A storage space where your project’s files and history are saved.

5️⃣ Common Git Commands:
- git init → Initialize a repo 
- git clone → Copy a repo 
- git add → Stage changes 
- git commit → Save changes 
- git push → Upload to remote 
- git pull → Fetch and merge from remote 
- git status → Check current state 
- git log → View commit history 

6️⃣ What is a Commit? 
A: A snapshot of your changes. Each commit has a unique ID (hash) and message.

7️⃣ What is a Branch?
A: A separate line of development. The default branch is usually main or master.

8️⃣ What is Merging? 
A: Combining changes from one branch into another.

9️⃣ What is a Pull Request (PR)?
A: A GitHub feature to propose changes, request reviews, and merge code into the main branch.

🔟 What is Forking?
A: Creating a personal copy of someone else’s repo to make changes independently.

1️⃣1️⃣ What is .gitignore? 
A: A file that tells Git which files/folders to ignore (e.g., logs, temp files, env variables).

1️⃣2️⃣ What is Staging Area? 
A: A space where changes are held before committing.

1️⃣3️⃣ Difference between Merge and Rebase
- Merge: Keeps all history, creates a merge commit 
- Rebase: Rewrites history, makes it linear 

1️⃣4️⃣ What is Git Workflow?
A: A set of rules like Git Flow, GitHub Flow, etc., for how teams manage branches and releases.

1️⃣5️⃣ How to Resolve Merge Conflicts?
A: Manually edit the conflicted files, mark resolved, then commit the changes.

💬 Tap ❤️ if you found this useful!