How to connect a frontend to its backend after deployment
Avoid localhost and CORS mistakes by separating browser URLs from private Docker service addresses.
App Cities · 2 min · Updated
Your frontend shows the page. Your backend does the work behind it. They need to talk to each other. A request from the browser needs a public URL. A request inside the pod can use a private Docker service name. These two addresses are not always the same.
The steps
- Find where each API request runs. Browser-side JavaScript and server-rendered requests may need different base URLs.
- Keep internal addresses for server-to-server calls. A Docker name such as api is useful inside Compose but is not a public hostname.
- For browser requests, route the API through the public web entry, often under /api. Configure that routing in your project's web service rather than assuming every container gets its own public URL.
- Check the browser network panel and backend logs together. Verify scheme, path, authentication cookies and allowed origins.
A common question
Does every service get a public address?
No. The project identifies its public web service. Internal APIs and databases can remain private behind that entry point.
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