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This page is for whoever packages the desktop build, not for end users. If you are using the app and see “Live Google Sheet sync isn’t switched on for this deployment yet”, that means this setup has not been done for your build — CSV import works regardless, and a synced sheet can be imported as a file.

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Why a setup step exists

The desktop app connects a Google Sheet through Google’s own OAuth, using the installed-app pattern: the user approves in their real browser, and Fin gets read access to exactly the one sheet they pick (drive.file scope) — never their whole Drive, never their Google password. That flow needs a Google OAuth client of type “Desktop app”, registered once. The client id ships in the binary (which is sanctioned for installed apps — PKCE is what protects the exchange, not a secret). Until a build carries one, the app honestly says the feature is not switched on rather than offering a button that fails.

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One-time registration

1

Create a Desktop app OAuth client

In the Google Cloud Console → APIs & Services → Credentials → Create credentials → OAuth client ID, choose application type Desktop app. Desktop clients permit loopback redirects on any port, which is what makes the OS-assigned local port work.
2

Enable the APIs

Enable the Google Sheets API and the Google Drive API for the project. The Drive API backs the drive.file scope; Sheets reads the rows.
3

Configure the consent screen for drive.file

drive.file is a non-sensitive scope (per-file access the user grants explicitly), so it does not require Google’s restricted-scope security assessment. Fill in the consent screen and publish it. Add test users while it is in testing.
4

Set the build's environment

The packaged desktop build reads these:No redirect URI needs pre-registering: desktop clients allow loopback, and the app computes http://127.0.0.1:<port>/api/feeds/google/desktop/callback from the running server.

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What the user then sees

With the client id present, the connector card offers Connect a Google Sheet: the user pastes their sheet’s link, a browser tab opens for approval, and the app completes the connection and proposes a column mapping — the same “check the columns” step the web app uses.

How sync behaves once connected

Fin reads the sheet on a schedule; rows are fingerprinted so re-reading the same sheet changes nothing, and a row that disappears is flagged rather than deleted.

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If approval fails to renew

Google issues a renewable authorisation only the first time a user approves an app. If a user connected before, revoked, and reconnects, they may get a one-hour token with nothing to renew. The app detects this and tells them to remove Fin from their Google account permissions and connect again — which makes Google issue a fresh renewable token.