Skip to main content

Backup & Sync

Open the Backup page from the extension popup or from Backup in the left sidebar (shown on every extension page). Not available in Incognito windows.

This page covers three independent features: automatic session backup, restoring a session from a backup file, and backing up/restoring your TMS settings. All three are optional, TMS works fully without ever touching this page, since it also keeps its own session history locally.

Automatic session backup​

What gets backed up​

On each run, TMS backs up your current session: every open window, its tabs (original URLs, not the internal suspended-page URL) and Chrome Tab Group assignments, the same data you'd get from an Export in Session Management, just automated and written to a file.

Enable automatic backup​

Backup page with automatic backup disabled, the default state

Since 9.0.1, this page shows a note reminding you that backup is off, with an option to snooze the reminder for 10 days or dismiss it permanently, see Backup activation nudge below.

Toggle Enable automatic backup. Since 9.0.1, doing so triggers Chrome's permission prompt for downloads right at that moment, not before, see Permissions for why. If you decline the prompt, the toggle reverts and nothing is enabled. Once enabled (and the permission granted), four settings become available:

SettingDescription
Device name (optional)A friendly label for this installation, e.g. "MacBook" or "Work PC". Shown as the group heading when restoring backups from a machine with more than one device. If left empty, the device's internal ID is used instead.
Backup intervalHow often TMS runs a backup: every 15 minutes, 30 minutes, 1, 2, 4, 8 hours, or once a day at a chosen time.
Backup destinationLocal (saved to your Downloads folder) or Google Drive (see below).
Max backups per deviceHow many backup files to keep before older ones are automatically deleted. Default 10, configurable from 2 to 50.

Click Backup now at any time to run a backup immediately, independent of the schedule. To prevent accidental spam, the button (and the "Save settings to Drive" button) is disabled for 30 seconds after each run, a countdown in the status bar shows when it re-enables.

Backup now button, next run time, and the device-identifier explanation

If a backup produces an empty result (no open windows/tabs to save), TMS silently skips it, no empty backup files are created.

Automatic backup enabled with destination set to Local

Dark theme:

Automatic backup settings in dark theme

Backup activation nudge​

Added in 9.0.1. If you've never turned on automatic backup, TMS shows a quiet reminder rather than nagging you with repeated pop-ups:

  • A small amber badge on the toolbar icon.
  • A banner in the extension popup, clicking it opens this page.
  • The note shown above, on this page.

Each surface offers Remind me in 10 days, which snoozes the reminder (badge, popup banner, and this note all reappear automatically once the snooze expires), or, from this page only, a permanent I'm not interested, stop reminding me checkbox. Once you enable automatic backup, or check that box, all three surfaces stay hidden until the corresponding condition changes again. Nothing about this reminder collects data or phones home, it only reads your own local Enable automatic backup setting.

Local backups​

Files are written to Downloads/tms-backups/tms-session-{deviceId}-{timestamp}.json. The {deviceId} is a random 8-character identifier generated once per browser installation and stored locally, it exists purely so that two browsers writing to the same Downloads folder (e.g. Chrome and Brave on the same machine) never overwrite each other's files. Rotation keeps only the newest Max backups per device files for this installation.

Save dialog popping up on every backup​

TMS saves local backups via chrome.downloads.download() with saveAs: false, which normally writes the file silently with no prompt. If Chrome's own setting "Ask where to save each file before downloading" (chrome://settings/downloads) is turned on, Chrome overrides that and shows its save-location dialog anyway, for every download, TMS included. This is Chrome's behavior, not something an extension can suppress or opt out of.

If scheduled backups are popping up a save window and stealing focus, turn that Chrome setting off (and set a default download folder) so backups save silently, or switch Backup destination to Google Drive, which doesn't go through the downloads dialog at all.

Google Drive​

Switching Backup destination to Google Drive before connecting an account shows a Connect Google Account prompt in place of the backup/disconnect buttons:

Backup destination set to Google Drive, not yet connected

Click Connect. Since 9.0.1, this first triggers Chrome's permission prompt for identity, requested at this point rather than upfront, before continuing into the standard Google OAuth consent flow: choose the account, then confirm access:

Google's "Choose an account" screen for the TMS Drive connection

Google's consent screen showing the narrow drive.appdata scope requested

TMS requests only the narrow drive.appdata scope, see Permissions for what that does and does not allow. Once connected you'll see the connected account and the destination folder shown on the page:

Backup page with Google Drive connected, showing account and folder

Backups on Drive live in a hidden, app-only folder (appDataFolder) that never appears in your regular Google Drive file list, this is also why there is no "open in Drive" link for it. Filenames follow the same tms-session-{deviceId}-{timestamp}.json pattern as local backups.

Multi-device rotation​

If you use TMS on more than one machine with the same Google account, each device's backups are rotated independently, a lightweight session synced from a laptop with three tabs open will never push out backups from your primary desktop's 40-tab session. This works via a small per-device registry file (tms-device-{deviceId}.json) that TMS keeps up to date with the device's friendly name and the time it last backed up.

Disconnecting​

The Disconnect button revokes the OAuth token (chrome.identity.removeCachedAuthToken + a call to Google's token-revocation endpoint). Existing backup files on Drive are not deleted, only the connection from this browser is removed.

If Drive authentication fails​

If a scheduled Drive backup fails because the connection expired or was revoked elsewhere, TMS shows a small red badge on the toolbar icon and a banner in the popup. Clicking the banner opens this page so you can reconnect.

Connecting on Brave or Vivaldi​

Fixed in 9.0.2, reworked in 9.0.3. Chrome's chrome.identity.getAuthToken() doesn't work on either browser: Brave attaches a custom URI scheme Google's backend rejects outright (a raw Error 400: invalid_request page), and Vivaldi disables Google sign-in entirely, so the connect flow used to hang with no feedback. TMS falls back to chrome.identity.launchWebAuthFlow() on these browsers, racing the original method against a timeout so a Vivaldi-style hang surfaces as a failure instead of hanging forever, and remembers which method worked per install so later connections skip straight to it. Once connected, this page shows a quiet second line under the "TMS Backups" folder name naming which OAuth method is active for the install, mainly useful for support.

9.0.2's version of this fallback used a short-lived (~1 hour) access token that needed the browser's help to silently renew, which Brave/Vivaldi don't support reliably, causing accounts to flip back to "disconnected" after just a backup or two. 9.0.3 replaces that with an authorization-code + PKCE exchange that mints a long-lived refresh token instead, renewed with a direct request that doesn't depend on the browser at all. That request is proxied through tms-oauth-proxy, a small Cloudflare Worker that holds the OAuth client's secret server-side so it never ships inside the extension package. The worker only ever sees the token-exchange request itself (authorization code or refresh token, nothing else), never your Drive data or the resulting access token, which stay entirely in your own browser's storage. See the 9.0.3 write-up for the full story.

Why a local file can still appear with Drive selected​

On browser shutdown, TMS writes an emergency local backup first regardless of your chosen destination, a Drive upload isn't reliable in that narrow shutdown window since the service worker can be killed mid-request. If your destination is Drive, that local file is queued and uploaded on the next startup, then automatically removed once the upload succeeds. Seeing a file appear locally even in Drive-only mode is expected behavior, not a bug, this is now explained directly on the page too, right below the multi-device rotation note.

Switching destination from Drive to Local​

If you switch the destination from Google Drive to Local, a dialog offers to import your most recent Drive backup directly into Saved sessions, a safety net so you don't lose access to that data just because you stopped using Drive. If Drive was never connected, or has no backups, this dialog is skipped.

Restore from backup​

A separate section below the backup settings, independent of whether automatic backup is currently enabled.

Restore from backup section, with a local file picker and a Drive backups dropdown

From a local file​

Click Restore from file, pick a tms-session-*.json file (from this machine's Downloads or copied from anywhere else), and TMS imports it as a new entry in Saved sessions, auto-named from its timestamp (e.g. "Backup 2026-06-24 09:30"). Open Session Management to actually reopen the tabs.

From Google Drive​

Shown only when Drive is connected. The dropdown lists every backup found in your Drive appDataFolder, grouped by device name (an optgroup per device, plus a "Legacy backups" group for files created before the multi-device format existed). Pick one and click Import, same outcome as the local flow: it lands in Saved sessions.

Browsing/downloading raw Drive files​

A collapsible Drive backup files panel lists every backup on Drive, grouped by device when more than one machine backs up to the same account, with each file's date and size, numbered sequentially. Each row offers:

  • Download: saves the raw .json to your local Downloads folder without importing it
  • Delete: permanently removes that one backup file from Drive, after a confirmation prompt

Since 9.0.2, each device group heading also has a Delete all button to remove every backup file for that device in one go, after a confirmation prompt listing the file count, instead of deleting them one by one.

Expanded Drive backup files panel with a numbered row and Download/Delete buttons

Settings backup​

Separate from session backup, this saves your TMS configuration (all the toggles in Settings, the never-suspend list, etc.), not your open tabs.

Settings backup section with Local and Google Drive cards, showing the last Drive backup date

Local​

  • Export downloads your current settings as a .json file.
  • Import loads a previously exported settings file and applies it (after confirmation).

Google Drive​

Shown only when Drive is connected.

  • Save settings to Drive uploads tms-settings.json to the same hidden appDataFolder. If a settings backup already exists, you're asked to confirm overwriting it, and TMS also keeps one extra safety copy (tms-settings-prev.json) of whatever was there before, so a mistaken overwrite is still recoverable.
  • Restore settings from Drive downloads and applies the current tms-settings.json, after confirmation.

The date of the last Drive settings backup is shown next to the section title once one exists.