cors

Rails.application.config.middleware.insert_before 0, Rack::Cors do
  allow do
    origins_list = if Rails.env.production?
                     ENV['CORS_ALLOWED_ORIGINS']&.split(',') || []
                   else
                     'localhost:3000', 'localhost:5173', /127\.0\.0\.1:\d+/

INSTALLED_APPS += ['corsheaders']

MIDDLEWARE = [
    'corsheaders.middleware.CorsMiddleware',  # Must be before CommonMiddleware
    'django.middleware.common.CommonMiddleware',
    # ... other middleware

Rails.application.config.middleware.insert_before 0, Rack::Cors do
  allow do
    origins 'https://app.example.com', 'https://admin.example.com'
    resource '/api/*',
      headers: %w[Authorization Content-Type],
      methods: %i[get post patch delete options],

const rawOrigins = process.env.ALLOWED_ORIGINS ?? "";

export const allowedOrigins = new Set(
  rawOrigins
    .split(",")
    .map((o) => o.trim())

package com.example.demo.config;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.cors.CorsConfiguration;
import org.springframework.web.cors.CorsConfigurationSource;

Rails.application.config.middleware.insert_before 0, Rack::Cors do
  # Development CORS - allow any localhost
  allow do
    origins(
      /http:\/\/localhost:\d+/,
      /http:\/\/127\.0\.0\.1:\d+/,

package middleware

import (
  "net/http"
)