Despite scrolling at approximately 5 frames per second in a crowded inbox, billions of people use Gmail every single day without mass-migrating to a “faster” email client. This should indicate something uncomfortable about how we spend our time as engineers. We treat performance like a moral virtue. A slow app is a bad app, built by lazy developers. A fast app is a good app, built by craftspeople.
Showing prices in a user's local currency increases trust, reduces bounce rates, and improves conversions — especially for international audiences. Here's how to do it automatically in React. Detect the user's currency from their IP address (no user input needed) Fetch the live exchange rate for that currency Format the price according to their locale // hooks/useCurrency.ts import { useEffect, us
IP geolocation is one of the most accessible fraud signals available. It won't stop sophisticated attackers, but it catches a significant amount of low-effort fraud with very little implementation overhead. Impossible travel: A user logs in from Germany, then from Brazil 10 minutes later. Country mismatch: Billing address is in the US, but the IP is in a different region. High-risk region matching
A walkthrough of prompt injection attacks against OopsSec Store's AI assistant, bypassing its input filters to extract a flag from the system prompt. OopsSec Store has an AI support assistant with a secret embedded in its system prompt. The only thing standing between us and the flag is a regex blocklist. Spoiler: four regexes are not enough. Initialize the OopsSec Store application: npx create-os
I have a confession. For years, when a developer proudly showed me their Python app — gray square buttons, a Listbox straight out of 1998 — I would politely nod. I've stopped doing that. Not because I turned mean. Because PyQt6 exists, and there's no excuse anymore. This article is my attempt to convince you — yes, you, the one still typing import tkinter out of habit — that something radically be
TL;DR — One API call subscribes a customer endpoint. Centrali signs each delivery with HMAC-SHA256, retries 5 times over ~40 minutes on failure, logs every attempt, and exposes a one-line replay endpoint. No queue. No retry logic. No Svix. The whole subscribe call is right below — scroll to it if you just want the shape. Your customers want webhooks. You know the checklist: A queue so user request
The Auth Gateway sits in front of every authenticated request in the platform. Its latency isn't just its own latency — it's the floor for every service behind it. If auth takes 50ms, every request to every upstream service starts 50ms in the hole. Our internal target is sub-millisecond on cache-hot paths. The way we hit it isn't clever algorithms — it's a stack of small caches, each one handling
JWTs have a hard problem hiding inside them: they're stateless. The whole point of a JWT is that the verifier can check a signature and make a decision — no database, no round-trip. That's what makes them fast. It's also what makes "log this user out right now" not work out of the box. We had to solve this. Users log out. Admins disable accounts. Service accounts rotate. Each one of those events h