You know it. You hate it. It is quite annoying when this dreaded error shows up when your app looks like a real product. That is CORS (Cross Origin Resource Sharing). It is not quite a bug, not quite a feature (I’m sure you’ve read this in the milli...
Outline Hook / Intro — relatable scenario of hitting a CORS error What is CORS? — simple definition Why Browsers Enforce It — the security reason How It Works — origins, request/response headers, preflight Common Causes of CORS Errors — real-wor...
The Bug I was trying to fetch daily horoscopes from a public API: https://horoscope-app-api.vercel.app/api/v1/get-horoscope/daily?sign=Virgo&day=TODAY Pasting the URL into the browser worked perfectly. I could see a JSON response like this: { "data...
Introduction Cross-Origin Resource Sharing (CORS) vulnerabilities can take many forms, and one of the most interesting variants involves trusting the "null" origin. In this article, we'll explore the PortSwigger Web Security Academy lab "CORS vulnera...
Introduction Cross-Origin Resource Sharing (CORS) vulnerabilities represent a significant security risk when misconfigured. In this walkthrough, we'll explore PortSwigger's "CORS vulnerability with basic origin reflection" lab, demonstrating how impr...
This is my current setup for all of my backend services, this CORS is based on my domain. (this one is generated by AI, I haven’t fully tested it) // Enable CORS app.enableCors({ origin: (origin, callback) => { // Allow requests with no...
If you’ve ever tried to upload or access files from a Cloudflare R2 bucket using a browser-based or client-side app and hit a wall with CORS (Cross-Origin Resource Sharing) errors, you’re not alone. This is a common challenge developers face when usi...
Modern web apps often fetch data from APIs hosted on different domains. But this can trigger security issues. That’s where CORS comes in. Let’s break down what CORS is, how it works, and how to handle CORS errors like a pro. 🌍 What is CORS? CORS (C...
Introduction Cross-Origin Resource Sharing (CORS) is simply a method or mechanism for integrating applications. This mechanism enables controlled access to resources or information located outside a specific domain. So, clients’ web applications in d...
Welcome to the definitive guide for building modern backend applications with Node.js and Express in 2025! Whether you're a beginner or an experienced developer looking to refresh your knowledge, this comprehensive tutorial will walk you through sett...
