Google just dropped a $99.99 screenless Fitbit Air band and used the occasion to announce something much bigger: the old Fitbit App is being upgraded to Google Health, and a completely rebuilt Google Health API is here. The new API ditches the old standalone authentication system and moves everything to Google Cloud and OAuth 2.0, making it far easier for developers to pipe heart rate, sleep data, and other personal health signals into AI applications.
https://twitter.com/_philschmid/status/2052781345831879145
The new API consolidates over 100 legacy endpoints into 31 core data types, from activity to blood oxygen (SpO2). Under the hood, Google introduced a "Reconciled Stream" mechanism that automatically handles data conflicts when multiple devices report overlapping readings. It also adds Webhook real-time notifications, granular read/write permission controls, and time-range aggregate query support.
This architectural shift dramatically expands what health data can power. Philipp Schmid, head of AI developer experience at Google DeepMind, says the streamlined API is ideal for building AI agents, MCP servers (a protocol component that connects large models to external data), or command-line tools that read personal sleep and calorie data.
But the overhaul comes with a hard deadline. Google's documentation confirms that the legacy Fitbit Web API will shut down in September 2026. Because the underlying authentication architecture has changed, existing access tokens won't migrate — every application must rewrite its code and ask users to re-authorize before the cutoff.
And this isn't the only Google API undergoing a breaking change — the Gemini API is also getting a major update that developers need to address by June.