What syncs between devices

Big-AGI is a local app that uses replica-based synchronization: every device holds its own full copy of your chats, personas and rambles. Any operation starts instantly on all of your data, and everything is searchable and editable, with visibility and permission. Edit on one device and the change appears on the others in real time.

What replicates, and what does not

Replicates pro	Conversations · Personas · Rambles
Stays on this device	API keys and configured models · Settings · Images and generated media

Keys never leave the browser through sync. A new device needs them pasted in, or restored from a backup file (Back up, restore, and import). A conversation held off the record is never written down at all, so it never syncs.

What does reach the server is isolated per account by row-level security in the database. No other account can read it.

Sync mirrors the current state, so a deletion or a bad edit propagates too. The copy that holds an earlier moment is a file you exported (Back up, restore, and import).

Why a device is empty

Sync runs only when four things are true at once: app startup complete, network connected, the backup toggle on, and a Pro subscription. The chip on the account page names the one that is false. Without Pro, move a file by hand instead (Back up, restore, and import).

Your phone

Big-AGI on a phone is the web app in the phone's browser; there is no native mobile app. Use the browser's Add to Home Screen or Install action: it launches without browser chrome and registers as its own device.

Installing changes the launcher, not the storage. On an empty phone, read the chip above: without Pro nothing was ever uploaded, and a backup file is the way across.

Offline, and the same chat on two devices

Work continues offline: everything is written locally regardless of sync state, and the queue drains when the connection returns. The app is installable, not offline-capable - with no network the page will not load, though data already there is untouched. A change reaches your other device over the live connection, or on the five-minute catch-up if that dropped.

A conflict shows both versions and waits for your choice:

Where	What it says	The button
on the item	"This chat has different versions on this device and in the cloud. Choose which to keep."	[ Resolve Conflict ]
Sync Conflict Detected	modal: Cloud Version | Local Version, Summary / Raw Data
keep local	Overwrite Cloud Version?	[ Keep Local & Sync ]
keep cloud	Replace Local Version?	[ Replace with Cloud ]
Auto Merge	offered only when the two differ trivially

Turning sync off

The toggle is a pause: it clears the queue and stops listening for changes, and removes nothing locally or in the cloud. Turn it back on and the queue refills.

Related

• Back up, restore, and import
• Accounts, Pro, and billing
• Chats live in this browser
• Open, Free, or Pro
• Where did my chats go?