Building a Full-Stack Habit Tracker with Claude Code - Part 2: Polish, Testing & Deployment Taking the habit tracker from MVP to production-ready with categories, analytics, comprehensive testing, and Vercel deployment In [Part 1], we built a fully functional habit tracker MVP in about 6-8 hours using Claude Code as our AI pair programmer. We had: ✅ Basic CRUD operations for habits ✅ Date-based
Every distributed system you build is already taking a side in the CAP trade-off. The question is whether you made that choice deliberately or discover it during an incident. CAP states that a distributed system can guarantee at most two of three properties: Consistency, Availability, and Partition Tolerance. The critical insight most teams miss — P is not optional. Networks fail. Pods crash. AZs
Testing Firefox Extensions with Playwright: End-to-End Testing Guide Extension testing is one of those things everyone knows they should do but few actually do. I've been using Playwright for end-to-end tests on the Weather & Clock Dashboard extension and it's changed how I think about extension quality. Unit tests don't cover the biggest failure modes: Does the extension actually load in Firefo
The most basic concept in test doubles is the dummy. When testing a function, there are usually two kinds of input: Meaningful input Data that affects the result of the function. Dummy input Data that is required by the function, but does not affect the behavior we are testing. Below is an example of meaningful data vs dummy data. This is a calculateShipping function: function calculateShip
Your application fetches a URL. The user supplied it. Your server makes the request, follows the redirect, and returns the content. The URL pointed to http://169.254.169.254/latest/metadata/iam/security-credentials/production-role. Your application just handed the attacker your cloud credentials. SSRF lets an attacker trick your server into making requests on their behalf — to internal services, c
How to Test Firefox Extensions Without Publishing: Local Development Tips Publishing to AMO every time you want to test a change is slow and painful. Here's the full toolkit for local development. The fastest way to load your extension: Open Firefox and go to about:debugging Click This Firefox in the left sidebar Click Load Temporary Add-on... Navigate to your extension folder and select manif
Em sistemas distribuídos modernos, garantir que todos os nós tenham exatamente os mesmos dados ao mesmo tempo pode ser caro, lento ou simplesmente inviável. É aí que entra o conceito de consistência eventual, um dos pilares fundamentais de arquiteturas escaláveis. O que é Consistência Eventual? Consistência eventual é um modelo de consistência onde, dado tempo suficiente e ausência de novas atuali
When people start working with high performance computing or parallel systems, “memory” often sounds like a background detail. It’s not. The way memory is structured can completely change how your applications behave, scale, and even fail. Let’s break it down in a practical way. ⸻ What is Shared Memory? In a shared memory system, all processors access the same memory space. Think of it