Blog

Writing

Notes on building software — architecture, tooling, and lessons learned.

AWSAWS SQSJavascript

AWS SQS Explained with a Real-World Example: A Complete Guide Using TypeScript

Learn how Amazon SQS works in real-world applications with simple TypeScript examples. Understand producers, consumers, queues, visibility timeout, dead letter queues, and scalable background processing through a practical e-commerce example.

Jul 9, 20265 min read

How to Write Logs That Actually Help When Something Breaks

Most logs look fine until the one night you actually need them. Here are three simple habits that turn a wall of useless text into logs your future self will thank you for.

Jul 6, 20265 min read

Javascript

Why var Prints 4 4 4 but let Prints 1 2 3 in JavaScript

Ever wondered why replacing `var` with `let` changes the output of a simple loop? Learn how JavaScript scope, closures, and the event loop work together, with real-world examples and interview insights.

Jul 4, 20264 min read

~/mahadi/blog

Rate Limiting You Can Watch Work

TypeScriptNestJS

TypeScriptNestJSRedis

Rate Limiting You Can Watch Work

What rate limiting is, with a bucket analogy anyone can follow — then how I built a distributed token-bucket limiter in NestJS + Redis with a live dashboard that shows requests getting throttled in real time.

Jun 24, 20263 min read

~/mahadi/blog

Supabase JWT Verification in NestJS

TypeScriptNestJS

Supabase JWT Verification in NestJS

Verifying Supabase access tokens locally with JWKS inside NestJS guards — no per-request calls to Supabase, with JIT user mirroring and admin promotion.

Jun 23, 20261 min read

~/mahadi/blog

Building a Portfolio Monorepo with Turborepo

TypeScriptNext.js

TypeScriptNext.jsNestJS

Building a Portfolio Monorepo with Turborepo

How this site is structured as a Turborepo monorepo: shared Zod contracts, a NestJS API, two Next.js apps, and the tooling that keeps it all coherent.

Jun 21, 20262 min read

TypeScriptNestJSNext.js

Type-Safe From Database to UI: Zod Contracts in a Turborepo

The bug that wastes the most time is the silent one where the API returns a slightly different shape than the frontend expects. Here is how a single Zod contracts package in a Turborepo kills that class of bug entirely.

Jun 10, 20262 min read1 comment★ 2

NestJSMicroservicesTypeScript

Designing a 14-Service NestJS Microservices Platform

What I learned decomposing a field-service product into 14 NestJS services — service boundaries, a shared Zod contract layer, an auth gateway, and async messaging — without drowning in distributed-systems complexity.

Jun 8, 20263 min read

~/mahadi/blog

Running an In-House Kafka Pipeline for a SaaS Ecosystem

Apache KafkaMicroservices

Apache KafkaMicroservicesNestJS

Running an In-House Kafka Pipeline for a SaaS Ecosystem

Why an interconnected SaaS suite needed its own event backbone, and how I ran a self-hosted Kafka pipeline — topic design, consumer groups, idempotency, and the failure modes you only learn in production.

May 28, 20263 min read

NestJSTypeScriptPostgreSQL

Multi-Level RBAC Done Right: Module → Feature → Resource

Role flags do not survive contact with a real enterprise app. Here is the three-tier access model — module, feature, resource — I built for a large manufacturing dashboard, and why each tier earns its place.

May 20, 20262 min read

~/mahadi/blog

Access + Refresh Tokens and MFA, Built From Scratch

NestJSTypeScript

NestJSTypeScriptRedis

Access + Refresh Tokens and MFA, Built From Scratch

Rolling your own auth is usually a mistake — but when you must, the details decide whether it is secure. Here is the access/refresh token + MFA design I built in NestJS, with the pitfalls that bite.

May 12, 20262 min read

~/mahadi/blog

Real-Time at Scale with Socket.IO

Socket.IONestJS

Socket.IONestJSTypeScript

Real-Time at Scale with Socket.IO

Real-time chat and a live calendar planner are easy on one server and surprising on three. Here is how I designed Socket.IO features in a NestJS ecosystem — rooms, presence, and scaling across instances.

Apr 30, 20262 min read

~/mahadi/blog

AWS in Production: Wiring S3, SES, SQS and EventBridge into NestJS

AWSNestJS

AWSNestJSTypeScript

AWS in Production: Wiring S3, SES, SQS and EventBridge into NestJS

A healthcare platform leans on a lot of AWS. Here is how S3, SES, SQS, Rekognition and EventBridge Scheduler fit into a NestJS API — what each one is actually for, and how to keep them testable.

Apr 15, 20262 min read

~/mahadi/blog

Background Jobs Without a Worker Fleet: SQS + EventBridge Scheduler

AWSNestJS

AWSNestJSTypeScript

Background Jobs Without a Worker Fleet: SQS + EventBridge Scheduler

Most “background job” problems are really two problems — work that should happen now-but-not-inline, and work that should happen later. Here is how I solve both on AWS without running a single always-on worker.

Apr 2, 20262 min read

~/mahadi/blog

An Edge-First TypeScript API Stack: Hono + Drizzle

HonoDrizzle

HonoDrizzleTypeScript

An Edge-First TypeScript API Stack: Hono + Drizzle

For a newer AI-agent platform I reached past the usual Express/Nest defaults for a lighter, edge-friendly stack. Here is what Hono and Drizzle buy you — and the trade-offs to go in with eyes open.

Mar 18, 20262 min read