Javascript

Introduction Cross-Origin Resource Sharing (CORS) is one of the most misunderstood parts of modern web development. It sits at the intersection of browsers, HTTP, and security, and when it goes wrong you often see opaque errors like “CORS policy: No ‘Access-Control-Allow-Origin’ header…”. This guide takes you from zero to hero: you’ll learn the mental model behind CORS, how the browser enforces it, how to configure servers correctly across popular stacks, how to optimize performance, and how to avoid common security pitfalls. ...

Introduction Expo Go is a cornerstone tool in the React Native ecosystem, enabling developers to build, test, and iterate on mobile apps rapidly without the overhead of compiling native code for every change. This tutorial dives deeply into how Expo Go works internally, revealing the architecture, workflows, and limitations that make it such a unique and powerful tool for mobile app development. By understanding Expo Go’s inner workings, you will better leverage its capabilities, troubleshoot issues, and know when to transition to custom development builds. ...

Table of Contents Introduction: Why Stripe for Your SaaS Core Concepts: Understanding Payment Processing Setup: Getting Started One-Time Payments: The Foundation Subscriptions: The SaaS Backbone Webhooks: Listening to Stripe Events Customer Management: Building Relationships Security: Protecting Your Business Testing: Getting It Right Production Checklist: Going Live Resources: Your Arsenal Introduction: Why Stripe for Your SaaS Stripe is the payment infrastructure that powers millions of businesses worldwide. For SaaS founders, it’s the gold standard because: ...

Table of Contents What is Supabase? Setting Up Your First Supabase Project Database Fundamentals Authentication (Auth) Row Level Security (RLS) Realtime Subscriptions Storage (File Uploads) Edge Functions Building a Complete SaaS Application Production Best Practices Resources What is Supabase? Supabase is an open-source Firebase alternative built on PostgreSQL. Think of it as your entire backend in a box: PostgreSQL Database: A real, powerful SQL database (not a limited NoSQL solution) Authentication: Email, OAuth, magic links - all handled for you Realtime: Live data updates without writing WebSocket code Storage: File uploads with CDN delivery Edge Functions: Serverless backend logic Auto-generated APIs: REST and GraphQL APIs created automatically from your database Why Supabase for SaaS? ...

Using OpenAI APIs in frontend code is risky — exposing your API key is a security hazard. The solution is a Cloudflare Worker that acts as a secure proxy. Your frontend calls the worker; the worker calls OpenAI with your key. The key stays secret. This guide is beginner-friendly, ELI5 style, and gradually moves to advanced techniques like streaming, caching, and rate-limiting. Beginner: Why You Need a Proxy Imagine you have a magic key that unlocks a powerful AI genie. If you give that key to everyone, anyone can spend your genie’s wishes. That’s what happens if you put your API key in frontend code. ...