Backend Development

What a backend does

Every app you use has a hidden half that stores data, enforces rules and talks to other systems. Learn what the backend is, what it does on each request and how it fits with the frontend and database.

HTTP in depth: methods, status codes and headers

HTTP is the language clients and servers speak. Learn the anatomy of a request and response, the main methods, the status codes you must know and the headers that matter, and try it yourself with curl.

Designing REST APIs

A well-designed API is easy to guess, easy to use and hard to misuse. Learn REST resource naming, how to map methods to actions, plus filtering, pagination, versioning and error format, using the Brew & Bean API.

Build an API with Node.js and Express

Build the Brew & Bean ordering API with Node.js and Express: routes, JSON bodies, validation, status codes, error handling and testing with curl. The same four endpoints appear in the FastAPI lesson.

Build an API with Python and FastAPI

Build the Brew & Bean ordering API with Python and FastAPI. Pydantic models give you automatic validation and free interactive docs. Same four endpoints as the Express lesson, so you can compare the two.

SQL and PostgreSQL for backend developers

Set up PostgreSQL, design the Brew & Bean tables, and learn the SQL a backend developer uses every day: SELECT, JOIN, GROUP BY, transactions, indexes and safe parameterised queries from Python or Node.js.

ORMs and migrations

Use SQLAlchemy to work with database rows as Python objects, and Alembic to change your database schema safely over time. You build the Brew & Bean models, create migrations, query, and connect it to FastAPI.

When to use NoSQL: MongoDB, Redis and DynamoDB

NoSQL is several different database designs, not one. Learn what MongoDB, Redis and DynamoDB are good and bad at, and how to choose from your data shape and queries, a common interview question.

Authentication: sessions, JWT and OAuth

Learn how login really works: store passwords safely with bcrypt, issue and verify JWTs in FastAPI, protect routes by role, compare sessions with tokens, and understand the OAuth flow behind Sign in with Google.

Validation and error handling

Never trust request data. Validate input with Pydantic models, compute totals on the server, return one consistent JSON error shape, and handle unexpected crashes safely, with the same pattern shown in Express with Zod.

Caching with Redis

Speed up an API by caching with Redis using the cache-aside pattern, keep the cache fresh with TTLs and invalidation, measure the speed-up, and build a simple rate limiter with atomic counters.

Background jobs and queues

Keep your API fast by moving slow work like SMS, email and PDFs into background jobs. Use FastAPI BackgroundTasks for small things, then build a Redis queue with a separate arq worker, retries and job status.

File uploads and object storage

Accept file uploads safely in FastAPI with type, size and content checks, then learn why production apps use object storage like S3 and presigned URLs so files go straight from the browser to storage.

Real-time: WebSockets and server-sent events

Push updates to users the moment they happen. Build live order tracking in FastAPI with both WebSockets and server-sent events, and learn how to choose between them, secure them and scale them.

Logging, metrics and health checks

When an API breaks in production you can't attach a debugger. Add structured JSON logs with request IDs, Prometheus metrics and liveness/readiness health checks to a FastAPI app, so you can see what it is doing and why it failed.

API security essentials

Learn the handful of mistakes behind most API breaches: broken access checks, injection, leaked data, missing limits and weak configuration. Fix each one with small, concrete code changes.

Containerise your backend with Docker

Package a FastAPI backend into a Docker image, run it as a container, and use Docker Compose to start it together with a Postgres database. This is the standard way teams ship backends.

Deploy a backend to the cloud

Take the Dockerised Brew & Bean API from your laptop to a public HTTPS URL. Learn the deployment checklist (config, database, health checks, logs) using Render as a worked example that applies to any host.

Project: library management API

Build a complete Library Management API with FastAPI and SQLAlchemy: books, members, loans, limits, fines in rupees and overdue reports. Add automated tests and containerise it. A portfolio-ready backend project.

GraphQL and gRPC: other API styles

REST is not the only way to build an API. Learn what GraphQL and gRPC are, what problems each solves, how a small GraphQL API looks in Python, and how to choose between REST, GraphQL and gRPC.