Six post-login problems every Flutter SaaS app must solve, developer warns

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A developer building a Flutter-based SaaS app identified six critical engineering challenges that arise after user login, which most starter kits ignore. These include token refresh race conditions, subscription state drift between client and backend, and the need for a multi-device push notification architecture. The article also highlights that app store-mandated account deletion does not automatically cancel active subscriptions, creating a potential billing issue for users. The developer recommends soft-deleting user records to preserve billing data while removing personal information. As a broader design principle, the post advocates building mock fallbacks for all external services so the app remains runnable before any API keys are configured.

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