Cloud Sync

Polar supports synchronizing the storage of your documents and annotations (known as our datastore) with the cloud and synchronizing data across computers.

Cloud sync is near real-time and actively pushes updates to your other devices so that when you change computers your documents are already up to date - no waiting (assuming your computer is active at the time).

Backed by Firebase

Polar cloud sync is backed by Google’s Firebase. You can read about the design in this blog post in the cloud sync infrastructure.

Security and Permissions

All documents in Polar are only available to your account and we use Google Firebase access control credentials to block unauthorized users (anyone other than you).

Future Features

Additionally, cloud sync was specifically designed to support additional features in the future including mobile, selective replication online collaboration, and other exciting new capabilities.

Selective replication is something we plan on adding in Q1 2019 and allows you to keep the majority if your documents in the cloud and selectively fetch them when necessary.

This enables users with massive repositories to free up disk space by keeping most of their data in the cloud.


Right now cloud sync is free for all users. We plan on making Polar cloud sync free for 95% users and the remaining 5% have the added benefit of supporting Polar with their monthly subscription fee.

We expect cloud sync to cost $7.99 per month for users with the largest document repository.