A local-first app with private backups you control

Cloud apps keep your work on their servers and lend it back to you. A local-first app with private backups turns that around: your data lives on your own computer, the app works without an internet connection, and you decide where copies go. Barside is built this way. Your notes, bookmarks, media and settings are saved on your drive as you work, and you need no account. One button exports everything to a ZIP file, a safety copy is made before every update and restore, and Barside Plus adds a daily cloud backup that is encrypted on your computer before it is uploaded.

This guide explains what local-first means, where Barside keeps your library, how each kind of backup works, and where the honest limits are.

What makes a local-first app with private backups

The term comes from a 2019 essay by the research lab Ink & Switch, "Local-first software: You own your data, in spite of the cloud", by Martin Kleppmann, Adam Wiggins, Peter van Hardenberg and Mark McGranaghan. In a cloud app, the server holds the real copy of your data, and your device holds a cache. A local-first app swaps the roles: the copy on your device is the primary one, and servers only hold secondary copies to help, for example with using several devices.

The essay sets out seven ideals: no waiting on a server, work that is not trapped on one device, a network that is optional, collaboration, work that lasts a long time, security and privacy by default, and your ownership and control. Private backups follow from the same idea. If the main copy is yours, the backups should be yours too: easy to make, checked before they change anything, and, when they leave your computer, readable only by you.

Where Barside keeps your library

Your library lives in one data folder on your computer:

Barside runs on Windows 10 and 11, on 64-bit Linux and on Mac.

• library.json holds your workspaces, notes, bookmarks, templates, Reading items, reminders and preferences.
• media/ holds the images, video, audio, drawings and saved webpages in your notes. Barside copies each file here, so moving or deleting the original never breaks a note.
• Open local data folder, in Settings, opens the exact place.

Barside saves carefully. It replaces the library file in one step, so a crash cannot leave half a file, and it keeps the previous version as library.json.bak. Do not edit these files while Barside is running. Saved passwords, AI keys and sign-ins are kept apart from the library, encrypted by your system.

There is no limit on notes or workspaces other than the free space on your drive. Barside counts which features are used, by name only, and you can turn that off in Settings.

What works offline, and what goes online

Offline, with no account:

• Notes, tasks, bookmarks, templates and reminders.
• Articles you saved in Reading, drawings, and the images, video and audio in your notes.
• Search, which matches words on your computer, and screen text, read by your computer's own text recognition.
• Speech to text for call transcripts and voice commands, after a one-time download of about 150 MB.

Online, only when you use it:

• Spaces, meetings and share links, after you sign in.
• Saving a page to Reading, newsletters, calendar updates and the research agent.
• The AI you connect, the leaked-password check, AI app connections through temporary web links, and app updates.
• Barside Plus: cloud backup, cloud sync and cloud agents, each off until you turn it on. To keep notes the same on several computers, see how to sync notes between computers.
• Support reports, only when you press Send to support on an error. A report says what went wrong, with a few settings and recent log lines, and never includes your notes or their titles, passwords, your clipboard or your files. See what a support report contains.
• Crash and error reports, on by default with a switch in Settings: when something breaks, Barside sends what went wrong and where in its own code, with your system and version, never your notes, files or who you are. See what a crash report contains.

Private backups in three layers

Export and restore a ZIP backup

1. Open Settings & backups and scroll to Take everything with you.
2. Click Export backup and choose where to save the file. It is named with the date, like Barside-backup-2026-09-28.zip. From any app, typing backup in the search bar opens the same save window.
3. To restore, install Barside on the other computer, open the same section and click Restore backup.
4. Pick the ZIP. Barside checks it, shows how many workspaces and notes it holds, and asks before it replaces anything. Confirm with Restore backup.

The ZIP holds every workspace and note, your bookmarks and groups, images, video and audio at their original quality, drawings, templates, Reading items with their highlights, reminders, the assistant's memory, your preferences, pinned notes and window positions. Barside checks a backup before it changes anything, and refuses unknown versions, missing media and unexpected file paths. It restores backups up to 8 GB of uncompressed contents. After a restore, nothing starts on its own: AI app connections are paused, and voice wake-up stays off until you turn it on again.

Automatic safety copies

• Before an update installs, Barside saves your library and makes a ZIP safety copy in its data folder. You choose when to restart, and an ordinary quit never installs an update.
• Before a restore, from a ZIP or from the cloud, Barside saves a safety copy of the library it is about to replace.
• On every save, the previous version stays as library.json.bak.

Encrypted cloud backup with Barside Plus

1. Open Settings → Cloud backup and choose Turn on cloud backup. It needs a Barside sign-in and Barside Plus.
2. Save your recovery key: 7 groups of 4 letters and digits, shown once. Use Copy or Save as a text file, then tick "I saved my recovery key somewhere safe."
3. From then on, Barside backs up once a day while it runs and your computer is online. Back up now runs one at once.
4. To go back to a day, open Restore a day and choose Restore this day. Barside downloads and checks everything first, and nothing on your computer changes until you click Restore now.
5. On a new computer, sign in, open Settings → Cloud backup, enter your recovery key and pick a day.

Everything is encrypted with AES-256-GCM on your computer before it is uploaded, with a key that only your computer and your recovery key can open. Barside's server sees when backups happen, their sizes, how many files they have, the Barside version and a random ID for each computer. It cannot see your notes, their titles, file names, or which files you have. It could still delete or withhold a backup, which is one more reason to keep a ZIP of your own.

Without your recovery key, nobody, not even Barside, can open your backups. Showing the key again later asks you to confirm it is you: with Windows Hello or your Windows password, with your desktop's password dialog on Linux, and with Touch ID or your Mac password in Barside for Mac. You get 50 GB: every backup of the last 24 hours, then one a day for 90 days, and each computer's newest backup is always kept. When the space is full, the oldest backups go first. Barside Plus costs US$20 a month or US$200 a year, plus sales tax, and if it ends, you can still restore for 30 days before the backups are deleted.

What is never in a backup

Some things are kept out of the ZIP export and the cloud backup on purpose:

• Saved passwords and two-step codes. They move with their own encrypted export; see the built-in password manager.
• Clipboard history.
• AI keys. Connect your AI again on a new computer.
• Sign-ins and connections: your Spaces sign-in, calendar addresses, AI app connections and share links.
• The speech engine and its models, which you install again in one step.
• Agents' pending approvals and their history, and recordings still in progress.

Cloud sync is optional, and not end-to-end encrypted

With Barside Plus, you can turn on Sync this PC (on Linux, Sync this computer, and in Barside for Mac Sync this Mac) in Settings → Cloud sync, on each of your computers. Your notes, workspaces, templates, repeating notes, agent settings, the assistant's memory and the files in your notes then stay the same on all of them, a few seconds after each change. Settings, such as your theme and mode, stay separate on each computer. A note changed on two computers at once keeps both versions, one named "(conflict copy)", and an edit beats a delete.

Be clear about the trade: synced content is stored on Barside's servers, encrypted in transit and at rest, but it is not end-to-end encrypted. The server can read it, which is what lets cloud agents work with your notes while your computers are off. Sync is off until you turn it on, and Delete the cloud copy removes it at any time, while each computer keeps its own notes. If you want your library on one computer only, leave sync off; the local library and the encrypted cloud backup work without it.

How Barside measures up to the seven ideals

Honest limits

• Notes and ZIP backups are not encrypted by Barside. Your computer's own security protects them, so use a sign-in password and disk encryption, and store ZIPs somewhere safe.
• Spaces and sync are online services. Spaces is hosted on Supabase and is not end-to-end encrypted either. Of Barside's online services, only cloud backup is encrypted on your computer before it is uploaded.
• No Markdown export. Barside does not export notes as Markdown files. Your data is readable JSON, and the ZIP is made for restoring into Barside.
• A restore replaces the library. It does not merge two libraries, which is why Barside makes a safety copy first.
• Old copies stay old. Deleting a note does not reach into backups you made earlier, or into copies already shared to a Space or sent to an AI company.

How it compares

Barside keeps your library on your computer in one app with notes, Reading, tasks, meetings and passwords, and it can import your notes from Notion, Evernote and Obsidian in a few minutes. To see how other apps handle the same ideas, compare the best local-first apps, or read the Obsidian alternative and Notion alternative guides. For the full picture of what Barside stores and sends, read the privacy guide and the details on cloud backup and cloud sync.

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