Migrating from the Fitbit Web API to the Google Health API

Following the consolidation of Fitbit and Google accounts, the legacy Fitbit Web API is being retired in favor of the new Google Health API — a Google-built cloud REST API for querying Fitbit user data over Google OAuth 2.0. Treat this as a real re-integration, not a flag flip: it is reported to bring a new developer console, a new OAuth provider, a new endpoint schema, and a new response format. The single biggest gotcha is that your existing Fitbit access and refresh tokens almost certainly do not transfer — every user is expected to re-sign-in with a Google Account and re-grant permissions. This migration is announced and in progress as of 2026, and the specific dates below come from vendor and community notices, so verify everything against current Fitbit and Google developer notices before you plan around it.

Why this is happening

Fitbit accounts are being folded into Google accounts, and the developer platform is moving with them. The legacy Fitbit Web API — reported to expose 120+ individual endpoints — is being replaced by the Google Health API, described as built from the ground up with bundled data types rather than the old per-endpoint model. If you have a working Fitbit integration today, none of this is a URL swap: you re-map endpoints to a new schema, adopt Google OAuth 2.0, and put your users through a fresh consent flow.

This page is the move. For how the Fitbit integration itself is built, see the Fitbit API integration guide. If the retirement is prompting you to reconsider the provider entirely, weigh the options in Fitbit API alternatives and the Fitbit API vs Garmin API comparison.

What actually changes

Because the two OAuth libraries differ, the recommended pattern is to run both in your codebase during the transition and put an abstraction layer over your health-data service, so the rest of your app does not care which path is live. That same insulation is what an aggregator can provide wholesale.

Dates: hedge hard, verify everything

From vendor and community notices (Fitbit Community, Google Health support threads, and aggregator blogs), the reported shape of the timeline is: users migrate their Fitbit login to a Google Account before roughly mid-May 2026; a side-by-side window runs into late September 2026; and the legacy Fitbit Web API is turned down (stops syncing) around September 2026. Do not present any of these as settled fact. They come from third-party notices and have room to move — confirm the current dates in the official Fitbit and Google Health developer notices before committing a cutover plan.

The migration, step by step

1. Audit your current Fitbit usage. List every Web API endpoint, scope, and data type you consume, your user volume, and where refresh tokens live.
2. Watch the official notices. Subscribe to the Fitbit developer/community and Google Health API notices, and treat every date as provisional until confirmed there.
3. Register on the Google Health API console and set up Google OAuth 2.0 credentials for the new app.
4. Map endpoints and schema. Build an old-endpoint → new-bundled-data-type table and adapt to the new response format; flag any data type without a confirmed equivalent.
5. Add an abstraction layer over your health-data service so the legacy Fitbit path and the Google Health path can coexist during the bridge window.
6. Plan mandatory re-auth. Design a re-consent flow that has every user sign in with Google and re-grant permissions — you cannot reuse Fitbit tokens. Communicate the account-consolidation step, since un-consolidated accounts reportedly cannot use the new API.
7. Run both paths in parallel during the side-by-side window; migrate users in cohorts and monitor for data gaps and auth failures.
8. Cut over before the legacy turndown, then decommission. Move remaining users before the reported September 2026 shutoff, keep a rollback path until you are confident, then retire the Fitbit Web API code.

Gotchas and how to keep users connected

• Tokens do not carry over. The change of OAuth provider means a hard re-consent for every user. Design the reconnect UX early and expect a long tail of users who need reminding — see keeping users connected during a migration.
• Account consolidation is a gate, not a detail. If a user has not migrated their Fitbit login to a Google Account, they may be locked out of the new API entirely. Surface that step in your messaging.
• Data-type parity is not guaranteed. The new API's coverage versus the old Web API is still evolving; verify each data type you depend on before promising it will still be there.
• Do not hard-cut. Run legacy and new in parallel, keep a rollback path, and let existing data keep flowing until each user reconnects.
• Consider an aggregator as insulation. A health-data aggregator that already supports both the legacy Fitbit Web API and the Google Health API can absorb the OAuth and schema change for you, so you keep a single integration instead of rebuilding. Vendors reported to be preparing for this include Terra, Validic, Thryve/Sahha, Fitabase, and Rook — verify each one's current support status before relying on it.

A note on effort and uncertainty

Budget for this as a re-integration: new credentials, a new schema mapping, a new OAuth flow, and a user-facing re-consent campaign — not an afternoon of config. The engineering is tractable, but the timeline is the risky part, because the dates here are drawn from third-party notices and can shift. Build the abstraction layer, run in parallel, and confirm the current cutover and account-consolidation dates against the official Fitbit and Google Health developer notices before you schedule anything. This is general engineering guidance; verify the live docs at publish time.