Connect a Flutter app to your API in production

The Flutter app runs on a phone; its API is a separate service that handles tasks such as login and saving data. Publishing the app to Google Play or the App Store does not publish that backend. You must deploy it at a public address and test the installed release.

Replace localhost with the public API address

localhost always means the device making the request. On a phone it points to the phone, not your development computer. In production, use a public HTTPS URL such as https://api.example.com. Confirm DNS, the certificate and the route’s expected response. Do not disable TLS checks to hide a certificate problem.

An emulator may use a development-only address to reach the host computer. A physical phone may need a reachable address on the local network. Keep these separate from the production build and verify which URL is actually compiled into the release.

Configure requests and validate responses

Flutter’s official networking recipe demonstrates the http package. Add it with flutter pub add http and keep the base URL in one place. A build-time value such as --dart-define=API_BASE_URL=https://api.example.com can select a public endpoint, but the compiled value can be inspected. It cannot protect passwords or private API keys.

Check the HTTP status and response type before decoding JSON. Handle authentication expiry, server errors, malformed data and offline connections in a way the user can recover from. Test a release build on both Android and iOS; a successful simulator request does not prove the store build uses the right endpoint.

Keep private keys on the backend

Anyone can inspect a mobile binary. Do not include database passwords, admin tokens or service credentials in Dart source, build variables or bundled assets. The API should authenticate each request and check that the user can act on the requested resource. Validate input, limit abusive requests and avoid writing tokens or personal data to logs. The OWASP REST Security Cheat Sheet covers common server-side controls.

Native Flutter requests do not use browser CORS rules. A separate Flutter Web client does, so diagnose which client is making the request before changing CORS settings.

Choose where the API runs

If your API is a service compatible with the current Projects plan, it may fit a Git-based deployment. If it needs system packages, multiple services or full server control, a VPS gives you that flexibility and the related work of updates, backups and security. Hostbrid provides hosting for the backend; you still build the API, manage its data and publish the mobile app. Compare Projects and VPS for mobile apps before choosing.

Before submission, check that the release has a public HTTPS URL, no localhost address or private credentials, and tested responses for success, authentication failure and network loss. Compare a custom API with Firebase and review the React Native production checklist if you support both mobile frameworks.

Before ordering, compare where to host an API: Projects or a VPS by runtime and maintenance responsibility.