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Writing on web development, AI, and building things.
How Does Instagram Check If a Username Is Taken Instantly? (Bloom Filters Explained)
You're signing up for a new account. You type a username — john — and before your finger even leaves the keyboard, a little red ✗ appears: "Username already taken." You try john_dev_2025, and instantl
Jun 21, 2026 · 10 min read
Understanding tempmail-checker — How It All Works
A deep-dive into the architecture, data structures, and algorithms behind tempmail-checker. Table of Contents The Problem The Naive Approach and Why It Falls Short Bloom Filters — The Core Innovat
Apr 11, 2026 · 17 min read
The 6-Digit Secret: How Authenticator Apps Verify OTP They Never Store
Authenticator apps have become the backbone of modern account security. When you enable two-factor authentication (2FA), you likely rely on tools like Google Authenticator or Microsoft Authenticator.
Apr 9, 2026 · 3 min read
npm vs npx: Same Family, Very Different Jobs
If you’ve been writing JavaScript for more than 10 minutes, you’ve seen npm and npx everywhere. And at some point, you probably thought: “Why do we even have both? Isn’t one enough?” Fair question.
Apr 3, 2026 · 2 min read