TapGPT: A Flutter client for ChatGPT

The product

TapGPT is a Flutter mobile client for interacting with the ChatGPT API. It supports authenticated accounts, multiple chat sessions, and synchronized conversation history across devices.

System design

• Flutter provides a shared iOS and Android interface.
• Firebase Authentication manages user accounts.
• Firestore stores and synchronizes conversations.
• Cloud functions protect server-side API access and isolate provider credentials from the client application.

Engineering focus

The project required careful coordination between a streaming conversational interface, persistent history, authentication state, and API usage limits. The data model keeps conversations separate while allowing the interface to update in real time.

Result

TapGPT demonstrates a complete mobile product around a hosted language model rather than a standalone chat screen. The surrounding account, storage, and API architecture is designed so the model layer can evolve without rewriting the entire application.