Similar to the dev Server proxy, the gateway, proxy or load balancer does the routing based on the configuration we provide, matching the HTTP path received in the request. In some cases, your load balancer would be sufficient if it can route to different endpoints based on HTTP paths. In the production environment, unless your frontend and backend API run inside the same web server, you need to set up a gateway or a proxy in front of them to serve from a single domain. module.exports = Īs an alternative approach, if you don’t want to use relative paths in the frontend for the backend API, you can start your web browser with specialized flags to disable CORS for local testing. The example below shows how you can add proxy configuration in the Webpack dev server. Since your development server is the middleman communicating with your backend API, it can safely avoid CORS. Inside the proxy configuration, you can define to forward any requests coming for the path /api to your frontend development server. When running the app locally, your frontend will try to access the backend API, using the same domain and port ( the browser won't have any concerns over CORS.Īt this stage, the proxy does its magic. When you use a proxy, you need to store only the relative path ( /api) in your frontend app. We can avoid all the above hassle by using the proxy configuration in frontend development servers. Here, the frontend and backend API domains are the same ( but the ports are different, where they are considered as different origins by the browser. Besides, you will also need to enable CORS in your backend API, allowing API calls coming from the frontend. Let’s assume your frontend app is running in, and backend API is running in Your frontend needs to store the backend API URL and port to run the app locally. So what precisely this proxy configuration do? Besides, Angular, React, and Vue come with Webpack dev server that has inbuilt support for proxy configuration. Most of these Node servers support proxy configuration. Today, most of the development servers we select for frontend development uses NodeJS. The development environment might also influence your setup in production, where you might deploy the frontend and backend API in different subdomains.īut do we need to go in this direction? Let’s look at ways to avoid CORS for both development and production environments.
Besides, we might even grant CORS in our backend API for development, since the development server for frontend and backend API might be running in two different ports.
Web browsers, won’t consider the preflight request if the web app use only the HTTP headers ( Accept, Accept-Language, DPR, Downlink, Save-Data, Viewport-Width, Width, Content-Language, Content-Type (Except the values application/x-In these apps, we define the backend API URL in the frontend as a variable for server operations. When it comes to Single Page Apps, usage of CORS is much more apparent. In most cases, the added delay is visible in web apps and adversely affects user experience.
So for each HTTP request trigged by the frontend, the browser needs to send two HTTP requests, increasing the overall response time. When your frontend sends an HTTP request to a different domain or subdomain, the browser will send an additional HTTP called preflight request, to see whether the server accepts messages from the sender’s domain. The most visible problem with CORS, besides security, is the impact on the performance in web apps. Still, you can enable CORS scoped to that particular feature. However, there could be special features like allowing to embed a page (e.g., Form, Video) outside your main web app domain, where you might consider enabling CORS in your backend. Exploring React components published on Bit.dev Do you need CORS?īut do we need to allow CORS for your web apps? I would say for most of the cases, you don’t need to worry about CORS since your web app is served from a single domain.
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