Tutorial
Four Ways a Refresh Token Request Fails — Only One Means Trouble
A refresh token system where every token is single-use and belongs to a token family. Invalid, expired, and revoked are routine. Reuse means a stolen ...
Tutorial
Background Jobs in NestJS with BullMQ: A Complete Walkthrough
A from-scratch background job pipeline in NestJS using BullMQ and Redis, demonstrated on an async LLM draft-generation endpoint — covering retry/backo...
Tutorial
Implementing Two-Factor Authentication (TOTP) in NestJS: With Full Source Code
A from-scratch implementation of TOTP-based two-factor authentication in NestJS, covering secret generation, QR code enrollment, partial vs. full JWTs...
Tutorial
IDOR Vulnerabilities in NestJS: How to Build Ownership Guards That Actually Protect Your Data
IDOR is OWASP's top API risk for a reason. A single missing ownership check can expose customer data across your entire application. This guide shows ...
Why Your App Is Slow (And It's Not the Database)
Slow APIs with a clean slow query log trace to one of five root causes. Four have nothing to do with query execution. Here's how to identify each one,...
SQL Mistakes That Kill Your Database (And How to Fix Them)
SQL performance problems rarely come from the database itself — they come from inefficient queries. This guide covers the most common mistakes that sl...
TypeORM is Killing Your Node Process: Handling Large Datasets Without OOM Crashes
Object-Relational Mappers (ORMs) are excellent for standard CRUD operations, relationship management, and schema migrations. But when you transition f...