Backend & APIs
Backend work is where a project stops being a demo. These articles cover building and shaping APIs, the authentication and caching decisions that follow, and enough of the networking and deployment layer that production stops being a mystery.
Building APIs
- API Testing With Postman: A Practical Guide The initial value of a Postman variable travels with the collection when you share it. The current value stays on your machine. Put your bearer token in the wrong box and you have just published it. Tutorial · 9 min read · August 6, 2026
- Redis Caching Basics: Cache-Aside, TTL and Invalidation A cached object comes back from Redis as JSON, so the Date you put in is now a string. The code that worked yesterday throws on line one, and only for cache hits. Tutorial · 12 min read · August 6, 2026
- WebSockets Explained: Handshake, Scaling and SSE Your chat app works perfectly until you run a second Node process behind a load balancer. Then half the messages never arrive, and nothing in the logs looks wrong. Tutorial · 12 min read · August 6, 2026
- ESM vs CommonJS: import, require and the type Field Adding one line to package.json can break every require in your project at once. Here is what the two module systems actually are and where they refuse to meet. Comparison · 12 min read · August 6, 2026
- Python JSON: load vs loads, and the Traps Between json.dumps on a datetime raises TypeError, and the default settings turn Hindi text into a wall of backslash-u escapes. Four functions, a handful of arguments, and a surprising number of ways to lose data. Tutorial · 10 min read · August 6, 2026
- EADDRINUSE: Port Already in Use and How to Fix It The process holding port 3000 is almost always your own server from ten minutes ago. Killing it blindly is the wrong habit; finding it takes one command. Tutorial · 11 min read · August 6, 2026
- SyntaxError: Unexpected Token and How to Locate It The line number in a SyntaxError is almost never the line with the mistake. And when the unexpected token is a less-than sign, your API returned an HTML error page. Tutorial · 11 min read · August 6, 2026
- Module Not Found: Fixing Cannot Resolve Errors The import works on your Windows laptop and fails on the Linux deploy box. That is not a mystery; it is your filesystem quietly ignoring capital letters. Tutorial · 11 min read · August 6, 2026
- Cannot GET /: Fixing Express Route Errors Cannot GET / is not an error at all. It is proof your server started perfectly and simply has no handler for that path, which means the fix is never in listen(). Tutorial · 11 min read · August 6, 2026
- Unhandled Promise Rejection in Node: Causes and Fixes One missing await turns a try/catch into decoration. The block completes, the promise rejects a moment later, and modern Node responds by killing your server. Tutorial · 11 min read · August 6, 2026
- Environment Variables Explained: Config Without Secrets in Code The first real security lesson most developers learn, usually the hard way — after committing an API key to a public repository. Tutorial · 10 min read · August 6, 2026
- npm vs Yarn vs pnpm: Which Package Manager to Use All three install packages. The differences are speed, disk usage and how strictly they enforce your dependency tree — and mixing them causes real problems. Comparison · 9 min read · August 6, 2026
- REST API Design: Practices That Make an API Usable An API is a user interface for developers. Most of what makes one pleasant is consistency, not cleverness. Tutorial · 11 min read · August 6, 2026
- Backend Developer Roadmap: A Practical Order to Learn In Backend is less about frameworks than about data, correctness and failure. This is the order that builds those, rather than a list of logos. Career · 12 min read · August 6, 2026
- How to Debug a 500 Internal Server Error A 500 tells you nothing except that the server failed. The logs tell you everything — and most people never look at them. Tutorial · 10 min read · August 6, 2026
- npm Errors Explained: ERESOLVE, EACCES, ENOENT and More npm errors look alarming and are mostly four recurring problems. Knowing which one you have turns a lost afternoon into a two-minute fix. Tutorial · 10 min read · August 6, 2026
- JWT Authentication Explained (and Where It Goes Wrong) A JWT is signed, not encrypted. Anyone holding one can read it — and confusing verify with decode is a complete authentication bypass. Tutorial · 11 min read · August 5, 2026
- REST vs GraphQL: An Honest Comparison GraphQL solves a real problem that most projects do not have. Knowing which problem is the difference between a good choice and cargo cult. Comparison · 10 min read · August 5, 2026
- HTTP Status Codes Explained: The Ones You Actually Meet The first digit tells you who has the problem. Getting 401 and 403 the wrong way round is the mistake almost every API makes at least once. Tutorial · 10 min read · August 5, 2026
- What Is CORS and How to Fix the Error The request worked in Postman and fails in the browser. Nothing is broken — you are meeting a rule that only browsers enforce. Tutorial · 10 min read · August 5, 2026
- JavaScript Fetch API Tutorial: Call APIs From the Browser A beginner-friendly guide to calling APIs from the browser with fetch: GET, POST, JSON, headers, error handling, and async/await, with working code. Tutorial · 9 min read · July 22, 2026
- How to Build a REST API with Node.js and Express A beginner-friendly, step-by-step tutorial: build a small REST API in Express with working GET, POST, PUT and DELETE routes you can run and test yourself. Tutorial · 9 min read · July 22, 2026
- What Is npm? Node Package Manager Explained A beginner-friendly guide to npm: what it does, how package.json and npm install work, and how to run npm scripts on your very first project. Tutorial · 9 min read · July 22, 2026
- What is an API? A Simple Explanation for Beginners An API lets two programs talk to each other. Learn what that means with a simple waiter analogy, plus REST, JSON, status codes, and a real fetch() demo. Tutorial · 9 min read · July 22, 2026
Auth, sessions and security
- OWASP Top 10 Explained: Ten Categories, Ten Fixes Most people memorise the ten names and still ship broken access control. The list names categories of failure, not specific bugs, and that gap is where projects get hit. Tutorial · 12 min read · August 6, 2026
- SQL Injection Explained: The Fix Is Not Escaping Quotes Two dashes typed into a login box can delete the password check from your own query. The fix is not smarter escaping, and most beginners reach for escaping first. Tutorial · 12 min read · August 6, 2026
- CSRF Explained: Why Your Own Cookie Attacks You The attacker never reads a single byte of the response, and the transfer still goes through. That is the part people misjudge about CSRF. Tutorial · 12 min read · August 6, 2026
- Password Hashing Explained: Why SHA-256 Is Wrong Here SHA-256 is a good hash. That is exactly the problem: it is fast, and speed is the one property you do not want when someone is guessing your users' passwords. Tutorial · 12 min read · August 6, 2026
- Cookies vs Sessions vs Tokens: What Is the Difference? These three get compared as if they were competing options. They are not — a cookie is a delivery mechanism, and it can carry either of the other two. Comparison · 10 min read · August 5, 2026
Performance and scale
- ORM vs Raw SQL: The N+1 Problem and When to Drop Down The loop that prints student.college.name runs one query per student. It is instant on your twenty-row dev database and it times out the moment real data arrives. Comparison · 12 min read · August 6, 2026
- HTTP Caching Explained: Cache-Control, ETag and Stale Deploys Caching is the cheapest performance win available — and the cause of the bug where users keep seeing an old version of your site after you deploy. Tutorial · 10 min read · August 6, 2026
- SQL Indexes Explained: When They Help and When They Hurt An index is the biggest single win available on a slow query — and the easiest thing to add so carelessly that it makes the database worse. Tutorial · 11 min read · August 5, 2026
Shipping it
- Bash Scripting Basics: Write a Script You Can Trust rm -rf "$DIR/"* with DIR unset expands to rm -rf /* and the shell will not stop you. Here is the small set of habits that separates a script you run in production from one you run once. Tutorial · 10 min read · August 6, 2026
- Nginx Basics for Developers: Reverse Proxy Explained Adding one slash to the end of proxy_pass changes the URL your backend receives. That single character is behind most of the 404s people blame on their router. Tutorial · 10 min read · August 6, 2026
- DNS Explained: Records, TTL and the Propagation Myth DNS propagation is not a thing. Nothing propagates. Old answers simply expire, on a clock you had to set before you made the change. Tutorial · 11 min read · August 6, 2026
- Python Logging: Why print() Is Not Enough logging.info() prints nothing on a fresh interpreter and never tells you why. The root logger defaults to WARNING, so your first three log lines vanish and you conclude logging is broken. Tutorial · 11 min read · August 6, 2026
- Docker for Beginners: What It Is and When You Need It Docker solves a real problem, and it is not the problem most beginners are told it solves. Here is what it is actually for. Tutorial · 11 min read · August 6, 2026
- What Is CI/CD? A Beginner's Explanation CI/CD sounds like enterprise infrastructure. It starts as one file that runs your tests whenever you push. Tutorial · 10 min read · August 6, 2026
More on Backend & APIs
- Database Transactions: ACID, Isolation and Deadlocks Two UPDATE statements in a row are not a transaction. Catching the exception does not undo the first one, and that is how money disappears from a wallet table. Tutorial · 12 min read · August 6, 2026
- MongoDB Schema Design: Embed or Reference? MongoDB will happily let one service store a pincode as a string and another store it as a number. Nothing errors. Your queries just quietly return half the results. Tutorial · 12 min read · August 6, 2026
- TCP vs UDP Explained: Reliability, Ordering and Cost TCP is reliable and UDP is not, says every textbook. The useful version is what happens on packet loss, and why TCP being a byte stream breaks more student projects than packet loss ever does. Comparison · 12 min read · August 6, 2026
- Java Streams: Where They Win and Where They Hurt A stream pipeline runs nothing until you ask it for a value, and it will refuse to run twice. Both facts explain most of the confusing bugs beginners hit. Tutorial · 11 min read · August 6, 2026
- Spread and Rest in JavaScript: Same Syntax, Opposite Jobs The same three dots do two opposite things depending on where you write them. And the copy they make is shallower than most people assume. Tutorial · 9 min read · August 5, 2026
- Frontend vs Backend vs Full Stack: Which Career Path Should You Choose? A plain, honest guide to frontend, backend, and full stack development — what each role does, who it suits, and how to choose your first path. Career · 8 min read · July 22, 2026