Are my private API origins uploaded anywhere?

No! All CORS header generation executes 100% locally in your browser memory.

Web Developer Tools

CORS Policy Generator

Generate Access-Control-Allow-Origin CORS security headers.

Developer & Code Suite

HTTP Security & CORS Policy Header Generator

ALLOWED ORIGIN DOMAIN

MAX AGE SECONDS (3600s)

GENERATED CORS SECURITY HEADERS

Access-Control-Allow-Origin: https://example.com
Access-Control-Allow-Methods: GET, POST, PUT, DELETE, OPTIONS
Access-Control-Allow-Headers: Content-Type, Authorization
Access-Control-Max-Age: 3600

About CORS Policy Generator

The Cross-Origin Resource Sharing (CORS) Header Studio constructs valid server response headers (`Access-Control-Allow-Origin`, `Access-Control-Allow-Methods`, `Access-Control-Allow-Headers`, `Access-Control-Allow-Credentials`, `Access-Control-Max-Age`) for REST APIs and CDNs.

Step-by-Step Guide

How to Use CORS Policy Generator

Step 1

Enter allowed origins (or choose wildcard `*`).

Step 2

Select allowed HTTP methods and custom request headers (e.g. `Authorization`, `X-Api-Key`).

Step 3

Toggle credentials support if sending cookies across origins.

Step 4

Copy the generated server configuration code.

Industry Scenarios

Practical Use Cases for CORS Policy Generator

Fixing Browser CORS Errors (`Blocked by CORS Policy`)

Resolve browser preflight `OPTIONS` blocks and configure explicit origin access for web apps consuming microservice REST APIs.

Configuring Cookie-Authenticated CORS Endpoints

Set `Access-Control-Allow-Credentials: true` with strict origin whitelisting for cross-origin cookie session authentication.

Sample Data & Transformation

Input & Output Examples

Generating CORS Configuration for API with Credentials

Input Sample:

Origin: https://app.example.com, Methods: GET,POST,PUT,DELETE, Credentials: true, Max-Age: 86400

Processed Result:

`Access-Control-Allow-Origin: https://app.example.com`\n`Access-Control-Allow-Methods: GET, POST, PUT, DELETE, OPTIONS`\n`Access-Control-Allow-Headers: Content-Type, Authorization`\n`Access-Control-Allow-Credentials: true`\n`Access-Control-Max-Age: 86400`

Technical Capabilities

Key Features & Performance

✓Generates all 5 core CORS headers with preflight `OPTIONS` status 204 handler snippets.
✓Supports Single Origin, Multiple Origin regex whitelisting, or Public API wildcard (`*`).
✓Code generator presets for Express.js (`cors()`), Next.js Route Handlers, Nginx `if ($request_method = OPTIONS)`, and FastAPI.
✓100% Client-Side memory execution.
✓1-Click Copy server CORS config.

Technical Glossary

Key Terminology & Definitions

CORS Preflight Request (`OPTIONS`)

An HTTP `OPTIONS` request sent automatically by browsers prior to complex cross-origin requests to verify server permission.

`Access-Control-Allow-Credentials`

A header indicating whether the response to the request can be exposed when the credentials flag is true; cannot be used with wildcard `*` origin.

Frequently Asked Questions (PAA)

CORS Policy Generator FAQs

The CORS specification forbids wildcard `*` origins when `Access-Control-Allow-Credentials: true` is enabled; the server must echo the exact requesting origin.