1. Decide which kind of SaaS app you are building

There are two common situations. Either you have a web SaaS with an API and paying customers and need a mobile app for it, or you are building a mobile-first SaaS product from scratch. The first is an integration project: match the existing account and plan model, add mobile-specific value, ship. The second is an MVP project: auth, one core workflow and a subscription on a backend that can grow.

2. Set the architecture: app, backend, entitlements

  • The app owns the interface, local caching and offline behaviour
  • The backend owns identity, data, billing state and entitlements
  • Subscription status is verified on the server and read by the app, never trusted from a local flag
  • A repository layer in the app isolates the API so screens never call endpoints directly

3. Authentication and onboarding

Use a managed identity provider (Firebase Auth or your existing one) with email, Google and Apple sign-in. Design onboarding to reach the first useful result before asking for a plan; users pay for value they have seen. Anonymous accounts that upgrade later are a good pattern for tools where sign-up is a barrier.

4. Subscriptions and payments

In-app subscriptions go through Google Play Billing and StoreKit, accessed from Flutter through in-app purchase packages. The backend validates purchases with the stores and stores entitlements per user. Build restore purchases, plan changes and account deletion from the start, because store review checks for them.

5. Backend, APIs and data

For a new product, Firebase covers auth, Firestore data, Cloud Functions logic, Storage and push with little infrastructure to run, and it scales with usage. For an existing SaaS, the app should use your API; the mobile-specific pieces are push registration, caching and any endpoints the mobile flows need that the web never did. Multi-tenant products need workspace scoping and role-based rules from day one, because retrofitting them is painful.

6. Push notifications, analytics and remote configuration

Send notifications from backend events, respect per-user preferences and deep link into the right screen. Track activation, retention and conversion events from the first release, and add crash reporting. Ship remote configuration so you can flag features, set minimum versions and control rollouts without a store release.

7. The admin panel

Your team needs to see users, plans, content and support issues without a developer. A web admin panel, which we build in Flutter, is part of the product, not an afterthought. Our own portfolio is operated this way, with an admin panel and Cloud Functions that manage configuration, notifications and release tracking.

8. Store rules and launch

Both stores require clear subscription pricing and terms, working restore purchases and account deletion. Complete the Data safety form and privacy labels from an audit of what the app really collects. Release with a staged rollout and watch crashes and conversion for the first week.