What is Flutter add-to-app?

Add-to-app is a way to add Flutter to existing native iOS and Android apps. It lets you adopt Flutter gradually - or just test it quickly - without committing to a massive rewrite.

Full rewrites of large enterprise applications carry a lot of risk and take a lot of time. Porting the UI is only part of the job - you also have to re-implement years of edge cases, business logic, platform-specific integrations, and institutional knowledge that lives in the codebase but not in anyone's head. In our experience, that knowledge has to be recovered whichever path you take, but a rewrite forces you to recover all of it before anything ships, and the launch is all-or-nothing. Meanwhile the native app still needs to be maintained and improved - the business can't pause shipping features while the rewrite is going on.

Add-to-app lets you embed Flutter screens directly inside your existing native applications. You can migrate the app gradually, feature by feature, and validate everything in production before moving further. It is not automatically the safer choice, though. When the native code is undocumented and nobody owns it anymore, a rewrite can turn out to be the lower-risk path - see the patterns we've seen for a case where it would have been.

You can also use it to run a quick prototype - replace one or a few screens in your native app with Flutter ones and see how it holds up. Give your stakeholders two phones, one with the current native app and one with the Flutter add-to-app integration. If the screens are done in a pixel-perfect manner, they shouldn't be able to tell the difference, which usually settles the discussion for stakeholders who are unsure about Flutter.