Free Online CORS Header Generator

Overview

A high-performance, single-file browser utility designed to help developers create accurate Cross-Origin Resource Sharing (CORS) configuration snippets. The tool simplifies complex header requirements into clean, copy-pasteable snippets for various web server environments.

Core Features

• Dynamic Configuration Form: Interactive inputs for Access-Control-Allow-Origin, Access-Control-Allow-Methods, Access-Control-Allow-Headers, Access-Control-Allow-Credentials, and Access-Control-Max-Age.
• Multi-Environment Output: Real-time generation of config code for Nginx, Apache (.htaccess), Express.js (Node), PHP, and Python.
• Live Preview: A live updated output window showing the formatted header directives.
• Copy-to-Clipboard: One-click functionality to copy specific configuration blocks.
• Educational Tooltips: Integrated help icons explaining what each CORS header does, assisting junior developers in understanding security implications.

Technical Implementation Specifications

• Architecture: Single HTML5 file containing internal CSS and Vanilla JavaScript.
• State Management: All application state is stored in memory using JS objects and variables. Constraint: ABSOLUTELY NO localStorage, sessionStorage, or Cookies.
• UI Frameworks: Utilize Tailwind CSS (via CDN) for styling. Implement Inter font (Google Fonts) for a modern SaaS aesthetic.
• Syntax Highlighting: Use a lightweight library like Prism.js (via CDN) to render code blocks with professional syntax coloring.
• Interaction Design:
  • Use soft, subtle box-shadows on input cards.
  • Smooth transition animations (ease-in-out) when switching between server environments.
  • Custom, non-blocking notification toasts for "Copied to Clipboard" success messages (avoiding alert() usage).

UI/UX Design Directives

• Color Palette: Strictly light-mode design. Use shades of slate (#f8fafc), white (#ffffff), and a primary "action" blue (#2563eb) for buttons and accents. Text should be high-contrast dark gray (#1e293b).
• Responsive Layout:
  • Mobile: Single column flow with stacked inputs.
  • Desktop: Two-column split. Left side: Input configuration controls. Right side: Output code snippets.
• Component Structure:
  • Header: Simple, clean branding with a descriptive H1.
  • Main Tool Area: Clearly segmented sections for inputs, toggle switches, and code output.
  • Accessibility: Ensure high contrast ratios and keyboard-navigable inputs for accessibility compliance.

Developer Guidelines

• Sandbox Safety: The app must function perfectly in a null-origin iframe.
• Performance: Keep the JavaScript bundle lightweight; avoid heavy dependencies. Vanilla JS preferred for all DOM manipulation.
• Asset Loading: All assets (Tailwind, Prism, Fonts) must be loaded via CDN links in the <head> section.
• Constraint: Strictly NO external trackers, analytics, or cookies.