Middleware Patterns
Master Express middleware — understand the request pipeline, write custom middleware, and apply it globally or per-route.
Environment Variables
Environment variables are a set of dynamic named values that can affect the way running processes will behave on a computer. They are part of the environment in which a process runs.
Layers Architecture
Layers are the functions that are executed in the order they are defined. We will learn about layers in this blog.
MongoDB - NoSQL Database
Use MongoDB from Express with Mongoose — schemas, models, CRUD, and aggregation pipelines.
PostgreSQL - Relational Database
Use PostgreSQL from Express with TypeORM — entities, CRUD, relations, and the QueryBuilder API.
Data Validation in API Requests
Validate request data with custom logic, Joi, and Mongoose — and how to pick the right approach.
Error Handling and Error Middleware
Master Express.js error handling with custom error middleware, error classes, async error wrapping, and best practices for production applications.
Authentication using JWT
JSON Web Token (JWT) is an open standard (RFC 7519) that defines a compact and self-contained way for securely transmitting information between parties as a JSON object. This information can be verified and trusted because it is digitally signed. JWTs can be signed using a secret (with the HMAC algorithm) or a public/private key pair using RSA.
Cookies
Cookies are small pieces of data stored in the client's browser. They are used to store information about the user's session (JWT, access token, refresh token, etc), preferences, tracking user activity, and other data that the server needs to remember.
CORS Policy
CORS policy is a security mechanism that allows restricting the resources implemented in web browsers. It prevents the JavaScript code from producing or consuming the requests against different origins.
Security & Rate Limiting
Harden your Express API with Helmet, rate limiting, input sanitization, and security best practices.
File Uploads with Multer
Sometimes we need to upload and store the file on the server, the file can be an image, video, audio, pdf, etc. In this tutorial, we will learn how to upload a file using the multer library, store the file in the server, and also how to retrieve the file from the server.
Filtration and Pagination using Query Parameters
Filter and paginate API results with query parameters using clean, reusable Express patterns.
View Engines
Render dynamic HTML on the server with EJS — setup, passing data to templates, and exporting HTML.
WebSockets
Add real-time, two-way communication to Express with WebSockets — connections, events, and broadcasting.
Testing Express Applications
Master testing Express.js applications with Jest and Supertest. Learn unit tests, integration tests, mocking, and test-driven development.
Express with TypeScript
We can also use TypeScript with Express, in this doc we will learn how to use TypeScript with Express.
AWS - Amazon Web Services
Integrate S3, SES, SQS, Cognito, DynamoDB, Secrets Manager, SNS, and CloudWatch from Express.
LLM Integration
Call LLM provider APIs from Express — text generation, tool use, conversations, and production patterns.
Deploying Express to Production
Deploy your Express API to a VPS (Ubuntu), configure Nginx as a reverse proxy, use PM2 for process management, and set up SSL.