nstance

" Each instance captures every tab and window, allowing users to revisit their exact browsing state at a later time or on a different device. This is particularly useful for those managing complex workflows or research sessions across multiple browsers and computers.

The extension preserves tab groups, including their colors, labels, and collapsed states, ensuring that sessions are restored exactly as they were. It supports tab group features for both Chrome and Firefox. Users can sign in with Google to sync sessions to Firestore, enabling seamless access between devices, but the tool also works fully offline with all data stored locally unless synchronization is enabled. Sessions can be exported as a single JSON file and imported on any machine or browser, with imported sessions tagged for easy identification of their origin. nstance is available as a dedicated extension for Chrome and Firefox, and is also compatible with Brave, Edge, and Opera. Sessions record which browser saved them, making cross-browser imports traceable.

Security is a core feature, with all session data encrypted using AES-256-GCM before leaving the user's device. URLs never touch Firestore in plaintext, and only the user's account can access their saved sessions. Additional user experience options are available, such as deleting tabs on load or save, ignoring pinned or grouped tabs, and a dark mode. Users can expand any session to view all contained tabs and open individual sites without restoring the entire session.

nstance is free to use, does not require an account to get started, and functions offline. Signing in is only necessary for cross-device synchronization. The tool is positioned as a session and tab management solution for browsers, focusing on organization, privacy, and accessibility across platforms.