Node.js & Express

Build backend services with Express: middleware, authentication, error handling, and API patterns — the backbone of Node.js interviews.

16 exercises

easyPython

Mock LLM API Client with Error Handling

Build a function that calls a mock LLM API with proper error handling for common API issues. Create a function `call_ll...

apierror-handlinghttp+7

mediumPython

FastAPI Dependency Injection Pattern

Build a FastAPI application with dependency injection patterns using database and authentication dependencies. **Requir...

fastapi

mediumPython

Flask Request Middleware with CORS, Logging, and API Key Authentication

# Flask Request Middleware Build Flask middleware using `before_request` and `after_request` hooks that handles: 1. **...

flask

mediumPython

FastAPI User Registration with Validation

Create a FastAPI application with a POST `/users` endpoint that validates user registration data using Pydantic models....

fastapi

easyTypeScript

Express Request Logging Middleware

Build an Express middleware function that logs information about every HTTP request and response. ## Requirements Your...

mediumTypeScript

Express Schema Validation Middleware

Create Express middleware that validates incoming request bodies against schema objects. The middleware should support:...

mediumTypeScript

Express Error Handling System

Build a robust error handling system for an Express application with three key components: 1. **Custom AppError Class**...

mediumTypeScript

JWT Authentication Middleware

Build JWT authentication middleware for an Express API with login and protected routes. ## Requirements Create an Expr...

mediumTypeScript

Next.js Middleware for Authentication

Build a Next.js middleware function that handles authentication for protected routes. Your middleware should: - Check f...

mediumTypeScript

User Data Fetcher with State Management

Build a data fetching component that loads users from a mock API and manages all possible states. ## Requirements Impl...

hardTypeScript

Express Error Handling Middleware System

Build a comprehensive error handling middleware system for Express that catches different types of errors and returns co...

mediumTypeScript

Product API with Pagination, Filtering, and Sorting

Build a RESTful API handler for a GET /products endpoint that supports advanced query features. ## Requirements Implem...

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