Which private browsers support extensions separate profiles and encrypted bookmark and history sync across devices?

If by “private browser” you mean privacy-focused browser + extensions + multiple profiles + end-to-end/client-side encrypted sync of bookmarks and history, the strongest matches are:

Firefox

Mozilla Firefox is probably the closest match to your complete requirement set.

• Extensions/add-ons can be synchronized between desktop Firefox installations.
• Bookmarks and browsing history can be synchronized.
• Firefox Sync encrypts the data before it leaves your device, and Mozilla says the encryption key isn't transmitted to its servers.
• Firefox supports separate browser profiles.
• Sync works across desktop, Android and iOS, although extension availability differs on mobile.

Brave

Brave is another very good fit, particularly if you want Chromium/Chrome-extension compatibility.

Brave Sync can synchronize bookmarks, history, extensions, open tabs, passwords and other data, and Brave describes the synced data as client-side encrypted.

Brave also supports browser profiles and Chrome Web Store extensions.

One distinction: Brave doesn't use a conventional account-based sync system. Devices join a Sync Chain using a code. That can actually be attractive if you don't want another browser account.

Vivaldi

Vivaldi also checks essentially all the boxes.

Its Sync supports:

• Bookmarks
• History
• Extensions
• Settings
• Passwords
• Open tabs
• Other browser data

Vivaldi explicitly states that the synced data is encrypted end-to-end, with the encryption password never sent to its servers.

The caveat is profiles: Vivaldi says that each synced user profile currently requires a separate Vivaldi account.

Bottom line

If your requirements are all mandatory, I'd narrow it to:

1. Firefox — particularly compelling if encrypted sync and independent profiles are your priorities.
2. Brave — particularly compelling if you want Chromium and broad Chrome-extension compatibility.
3. Vivaldi — particularly compelling if you want extensive browser customization and don't mind its profile/account approach.

One important distinction: “encrypted sync” isn't necessarily the same as “zero-knowledge sync.” Firefox, Brave, and Vivaldi all document client-side/E2E-style encryption for their sync data, but their architectures and metadata handling differ. Vivaldi, for example, says it retains certain metadata about encrypted sync entries.

If you tell me Windows/macOS/Linux + iPhone/Android and whether you need profiles to sync independently, I can narrow this down further.

No mainstream privacy-first browser natively supports end-to-end encrypted (E2EE) history sync alongside separate profiles and extensions , because storing browsing history on a cloud server fundamentally compromises strict zero-knowledge threat models. However, a few mainstream and power-user options hit different combinations of your criteria.

Comparison of Privacy & Power-User Browsers

Detailed Breakdown

1. Mozilla Firefox (with a Custom Sync Passphrase)
   • Extensions: Full support via Firefox Add-ons.
   • Profiles: Native support via about:profiles or the Profile Manager.
   • Encrypted Sync: Firefox Sync encrypts your data client-side using your account credentials, and you can set an additional Account Passphrase for true zero-knowledge end-to-end encryption covering bookmarks, history, tabs, and passwords across devices.
   • Privacy Caveat: Telemetry is enabled by default, requiring manual opt-out in settings.
2. Brave Browser
   • Extensions: Full support (Chromium-based).
   • Profiles: Native multi-profile support.
   • Encrypted Sync: Brave uses Brave Sync chained via a sync-code passphrase. It securely syncs bookmarks, extensions, and settings across devices, but does not sync browsing history to the cloud by design to protect privacy.
3. Ghost Browser
   • Extensions: Compatible with Chrome Extensions.
   • Profiles: Built entirely around isolated identity profiles ("Workspaces").
   • Encrypted Sync: Offers Private Data Sync utilizing AES-256 encryption where you manage your own sync storage (using custom servers or personal cloud storage).

If you want to achieve this setup, would you prefer to tweak Firefox with a custom privacy configuration and a sync passphrase, or are you looking for a Chromium-based alternative that compromises slightly on history sync?

Yes. If your requirements are privacy-focused browsing + extensions + separate profiles + end-to-end/client-side encrypted sync of bookmarks and history, the shortlist is fairly small.

1. Firefox — best match

Firefox Sync can synchronize bookmarks, browsing history, extensions, open tabs, passwords and settings. Mozilla says Sync encrypts data before it leaves your device, with the encryption key not transmitted to Mozilla.

Firefox also has genuine browser profiles, with separate extensions, bookmarks, settings, history, etc. stored in each profile.

Important caveat: extension syncing between desktop and mobile is limited; desktop extensions don't sync to Firefox's mobile versions.

Verdict: ⭐⭐⭐⭐⭐ If privacy is more important than Chromium compatibility, this is probably the one I'd choose.

2. Brave — best if you want Chromium

Brave Sync uses client-side encryption: Brave says synced bookmarks, passwords and other data are stored in encrypted form, with the decryption key kept on your devices.

It supports syncing across desktop, Android and iOS, including browsing history and bookmarks.

You also get Chromium's extension ecosystem and Brave's built-in tracker/ad blocking.

One nuance: Brave's Sync server still retains some unencrypted metadata such as device information and sync-item identifiers; the actual synced content is encrypted.

Verdict: ⭐⭐⭐⭐⭐ Probably the best choice if you want Chrome-compatible extensions without using Chrome/Google Sync.

3. Vivaldi — surprisingly strong

Vivaldi Sync supports bookmarks, history, extensions, passwords, settings, open tabs, reading lists and more, and Vivaldi explicitly says the synchronized data is encrypted end-to-end using an encryption password that isn't sent to its servers.

It also supports separate browser profiles. One unusual limitation is that each profile requires its own Vivaldi account for profile syncing.

Verdict: ⭐⭐⭐⭐½ Excellent if you want privacy and a highly customizable/power-user browser.

What I would choose

• Maximum privacy + open-source ethos: Firefox
• Privacy + Chrome/Chromium extensions: Brave
• Privacy + extreme customization: Vivaldi
• Maximum anti-tracking, but you don't need sync: Mullvad Browser

One particularly important distinction: "encrypted sync" isn't necessarily the same as "zero-knowledge sync." Firefox and Brave encrypt the sensitive synced content client-side, while some metadata can still be visible to the sync service. Vivaldi likewise says it retains certain sync metadata even though the data itself is encrypted.

If you tell me whether you're on Windows/macOS/Linux + Android/iPhone, I can narrow this down to the best 1–2 options and specifically compare profile isolation, extension syncing, history syncing, and what the sync provider can actually see.

Important caveat: extension syncing between desktop and mobile is limited; desktop extensions don't sync to Firefox's mobile versions.

Verdict: ⭐⭐⭐⭐⭐ If privacy is more important than Chromium compatibility, this is probably the one I'd choose.

2. Brave — best if you want Chromium

Brave Sync uses client-side encryption: Brave says synced bookmarks, passwords and other data are stored in encrypted form, with the decryption key kept on your devices.

It supports syncing across desktop, Android and iOS, including browsing history and bookmarks.

You also get Chromium's extension ecosystem and Brave's built-in tracker/ad blocking.

One nuance: Brave's Sync server still retains some unencrypted metadata such as device information and sync-item identifiers; the actual synced content is encrypted.

Verdict: ⭐⭐⭐⭐⭐ Probably the best choice if you want Chrome-compatible extensions without using Chrome/Google Sync.

3. Vivaldi — surprisingly strong

Vivaldi Sync supports bookmarks, history, extensions, passwords, settings, open tabs, reading lists and more, and Vivaldi explicitly says the synchronized data is encrypted end-to-end using an encryption password that isn't sent to its servers.

It also supports separate browser profiles. One unusual limitation is that each profile requires its own Vivaldi account for profile syncing.

Finding a browser that checks all of these boxes is surprisingly difficult because true "private-by-design" browsers (like Mullvad Browser or LibreWolf) intentionally disable sync and persistent history/sessions to prevent data leaks.

However, mainstream privacy-focused browsers that utilize client-side or zero-knowledge encryption do support this combination.

The Top Contender: Brave Browser

Brave is the primary option that comfortably fulfills every single requirement on your list.

• Extensions: Fully supported (compatible with the Chrome Web Store).
• Separate Profiles: Supports completely isolated local user profiles, each capable of managing its own independent extensions, bookmarks, and cookie jars.
• Encrypted Sync: Uses a decentralized Sync Chain encrypted locally at the client level using a sync phrase. Brave-operated servers cannot read your synced bookmarks, history, or settings.
• The Catch: Brave is privacy-focused rather than strictly "incognito-only." It saves history and bookmarks locally by default (unless you use a private window), but it allows you to sync that data securely across devices.

Alternative Option: Firefox (with a Custom Sync/Account Setup)

Standard Mozilla Firefox is open-source and respects privacy more than Chromium-based alternatives, though it requires trusting Mozilla's ecosystem architecture.

• Extensions: Fully supported (including on mobile via Android).
• Separate Profiles: Supported via the robust profile manager (about:profiles).
• Encrypted Sync: Offers end-to-end encrypted Firefox Sync for history, bookmarks, tabs, and passwords, protected by your Mozilla Account password (using a secondary/custom sync passphrase if you want extra zero-knowledge key security).
• The Catch: Out-of-the-box telemetry and data collection need to be manually toggled off in settings for maximum privacy.

Why Strict "No-Log" Private Browsers Exclude This

Browsers like Mullvad Browser or LibreWolf intentionally omit sync and persistent history features:

• Mullvad Browser runs in a permanent private/incognito mode, wiping history, cache, and cookies on exit, meaning cloud history sync undermines its anti-tracking and anti-fingerprinting architecture.
• LibreWolf strips out sync entirely to detach entirely from Mozilla's synchronization servers and telemetry hooks.

Would you like to explore how Brave's Sync Chain works compared to a traditional account login, or look into setting up isolated profiles in Firefox?

If you mean privacy-focused browsers that provide all (or most) of these features:

• ✅ browser extensions
• ✅ separate profiles/containers
• ✅ encrypted bookmark + history sync across devices

the list is fairly short. Here are the strongest options:

Best matches

1. Firefox — closest to your requirements

Mozilla Firefox is probably the best fit if you want privacy and convenience.

Supports:

• Extensions
• Multiple profiles (desktop)
• Containers for separating identities (work/personal/accounts)
• Firefox Sync for: - bookmarks
• history
• tabs
• passwords
• settings
• add-ons

Firefox Sync encrypts synced data before it is stored, with keys derived from your account credentials. It is one of the few mainstream browsers with a strong privacy-oriented sync design.

2. Brave — best Chromium-based option

Brave Browser gives you:

• Chrome extension compatibility
• Separate browser profiles
• Encrypted Sync Chain between devices
• Built-in tracker blocking

Good if you need Chrome compatibility but want less Google dependence.

3. Vivaldi — best power-user option

Vivaldi Browser supports:

• Chromium extensions
• Multiple profiles
• Encrypted sync for bookmarks, history, tabs, passwords, settings

It is less privacy-minimalist than Firefox or Brave, but offers more customization.

If you want true private encrypted sync independent of the browser vendor

A good approach is:

Firefox or Brave + a separate encrypted sync tool

Examples:

• floccus — syncs bookmarks using your own storage (Nextcloud/WebDAV/etc.) and supports encryption options.
• Konode — designed to sync Chromium browser data such as bookmarks, tabs, history, and extension lists using your own storage with optional encryption.
• MarkSync — encrypted bookmark sync across different browsers.

My recommendation by priority

• Maximum privacy + practical daily use: Firefox + containers
• Need Chrome extensions: Brave
• Need lots of customization: Vivaldi
• Need your own encrypted sync server/control: Firefox/Brave + floccus/Konode-style tools
• Need anonymity more than convenience: Tor Browser or Mullvad Browser

If you specifically need multiple isolated identities (work/personal/banking) plus encrypted sync, Firefox is the strongest match.

Finding a browser that checks every single box —private/secure architecture, extension support, separate local profiles, and end-to-end encrypted (E2E) sync for history and bookmarks across devices—is a narrow niche. True high-privacy "hardened" browsers (like Mullvad or LibreWolf ) intentionally disable cloud sync to prevent data leaks, while mainstream private alternatives balance convenience differently.

The primary options that support these features, and how they stack up against your criteria, include:

• Vivaldi
  • Extensions : Full support (Chromium-based, works with the Chrome Web Store).
  • Separate Profiles : Excellent native multi-user profile management.
  • Encrypted Sync : End-to-end encrypted sync (encrypted with a user-defined password on your local device before touching servers) for bookmarks, history, open tabs, and settings.
  • Privacy Context : While feature-rich and privacy-respecting (hosted on servers in Iceland with an open-source frontend), it is closed-source on the backend and telemetry-adjacent compared to hardcore privacy tools, though it handles your sync requirements better than almost any other power-user browser. You can read more about it on the Vivaldi Sync Help Page.
• Mozilla Firefox (Hardened / Configured)
  • Extensions : Full support (uses its own extension ecosystem, excellent support for uBlock Origin).
  • Separate Profiles : Built-in profile manager (about:profiles ) allowing complete local separation.
  • Encrypted Sync: Mozilla Firefox Sync uses end-to-end encryption via a master account password to sync bookmarks, history, and extensions seamlessly across devices.
  • Privacy Context : Out of the box, standard Firefox sends telemetry and isn't strictly "private," but it can be heavily configured or run via privacy modifications to meet your standards while keeping native encrypted sync intact.
• Brave Browser
  • Extensions : Full support (Chromium-based).
  • Separate Profiles : Supports separate local user profiles.
  • Encrypted Sync : Uses Brave Sync v2 , which is zero-knowledge and end-to-end encrypted. The catch: Brave syncs data across a peer-to-peer sync chain, but natively synchronizing distinct separate profiles independently across multiple devices without mingling history/bookmarks across those specific sub-profiles requires a workaround (manually pairing separate chains per profile) rather than a clean multi-account profile cloud sync.
• Note on Hardened Alternatives (Mullvad / LibreWolf / Tor) : Browsers like Mullvad Browser or LibreWolf intentionally omit cloud sync and accounts entirely by design to eliminate metadata leakage, server tracking, and fingerprinting vectors, meaning they cannot fulfill the cross-device sync requirement.

To help narrow down the best fit, tell me:

• Are you looking for a Chromium-based or Firefox-based environment?
• How critical is it that the browser is open-source versus feature-heavy?

If by “private” you mean privacy-focused browsers—not just private/incognito mode—the strongest matches are Vivaldi, Firefox, and Brave, but they differ substantially on profiles and sync.

1. Vivaldi — best match

Vivaldi is probably the closest to your exact requirements.

• Extensions: Yes.
• Separate profiles: Yes. Each profile gets its own extensions, bookmarks, cookies, history, settings, etc.
• Bookmarks: Syncs across devices.
• Full browsing history: Syncs across devices.
• Encryption: Sync data is end-to-end encrypted using an encryption password that isn't sent to Vivaldi.
• Extensions: Vivaldi Sync supports extension synchronization.
• Profiles: The catch is that each profile currently needs its own Vivaldi account for profile syncing.

This is the one I'd pick if you want a Chrome-like browser with strong built-in privacy controls, multiple isolated profiles, extensions, and genuinely encrypted history/bookmark sync.

2. Firefox — best privacy-oriented alternative

Firefox also checks most of the boxes:

• Extensions: Yes.
• Profiles: Yes.
• Bookmarks: Sync.
• History: Sync.
• Extensions/add-ons: Sync between desktop Firefox installations.
• Encrypted Sync: Firefox Sync encrypts synced data before it reaches Mozilla's servers; your account credentials/keys are used to protect the data.

Mozilla specifically documents syncing bookmarks, browsing history, add-ons, passwords, open tabs, and settings across devices/profiles.

The main limitation is that extension synchronization doesn't extend to desktop extensions on mobile Firefox.

3. Brave — good if you want Chromium

Brave Sync is also designed around encrypted sync data. Brave says its current Sync system uses encrypted data records, with the data encrypted on the client so that only you can see it.

It's a good choice if you specifically want:

• Chromium compatibility
• Chrome Web Store extensions
• strong anti-tracking defaults
• encrypted sync
• multiple devices

However, Vivaldi is a better fit if separate profiles and profile-specific data are central to your requirements.

What about Mullvad Browser?

Mullvad Browser is excellent for fingerprinting resistance and minimizing tracking, but it deliberately doesn't try to be a cloud-synced personal browser. So it doesn't satisfy your encrypted bookmark/history sync requirement.

My ranking for your exact requirements

Vivaldi > Firefox > Brave > Mullvad Browser

If your priority is specifically:

“I want Work / Personal / Banking profiles, each with different extensions and bookmarks, while securely syncing my bookmarks and browsing history between my PC and phone.” I'd choose Vivaldi first.

If your priority is instead:

“I want the strongest privacy philosophy and don't mind some compromises in Chromium compatibility.” I'd choose Firefox.

One important distinction: encrypted sync doesn't necessarily mean the entire browser profile is end-to-end encrypted. The specific synced data types and metadata matter. Vivaldi is particularly explicit about E2E encryption of its Sync data.

If you tell me whether you're on Windows/macOS/Linux + Android/iPhone, I can narrow this down further—including which one gives you the best profile isolation + extension sync + history sync combination across your exact devices.

Finding a private browser that checks every single one of these boxes—support for extensions, separate local profiles, and end-to-end encrypted (E2EE) sync for bookmarks and history across devices—is surprisingly tricky. Most hyper-focused privacy browsers intentionally omit cloud sync entirely to prevent data leakage, while mainstream browsers with great sync lack native strict privacy.

The options below fit these criteria to varying degrees:

1. Brave Browser (The Closest Match)

Brave is a Chromium-based browser built with a heavy emphasis on out-of-the-box privacy (blocking trackers, scripts, and fingerprinting vectors).

• Extensions: Fully supports standard Chrome/Chromium extensions from the Chrome Web Store.
• Separate Profiles: Supports multiple distinct local browser profiles, allowing you to separate work, personal, or specific project environments.
• Encrypted Sync: Features Brave Sync , which uses client-side encryption (via a sync chain code that only your devices hold). It syncs bookmarks, history, open tabs, passwords, and extensions across your devices without Brave being able to read the data.
• The Catch: Though telemetry and Google account hooks are stripped out, it is still built on the Chromium engine, which purists argue compromises deep-level independence.

2. Mozilla Firefox (With Custom Hardening / Account Sync)

While vanilla Firefox is not strictly marketed as a "private browser," it features robust tracking protection and can be easily hardened via about:config or extensions like uBlock Origin.

• Extensions: Exceptional support for desktop and mobile extensions.
• Separate Profiles: Features a native, robust Profile Manager (about:profiles ) to keep completely separate environments, cookies, and local extensions isolated.
• Encrypted Sync: Uses a Mozilla Account which encrypts your synced data (bookmarks, history, passwords, tabs) end-to-end on Mozilla's servers using keys derived from your account password.
• The Catch: Firefox does not natively sync extension settings or install state seamlessly across distinct devices out-of-the-box in the way it handles bookmarks/history, and standard Firefox telemetry needs to be manually disabled in settings for optimal privacy. Hardened forks like LibreWolf or Mullvad Browser strip out the Mozilla account/sync system entirely in the name of anonymity, meaning you lose cross-device sync if you go that route.

Comparison Overview

If you want to narrow this down, let me know:

• Do you prioritize Chromium or Firefox-based architecture?
• Is cross-device sync a non-negotiable requirement , or would you accept a local-only setup if it offered maximum anonymity?

Finding a browser that checks all of these boxes—private/privacy-focused, extensions support, separate local profiles , and end-to-end encrypted (E2EE) sync for both bookmarks and history across devices —narrows down the field significantly. Most ultra-minimalist or strictly "incognito-only" browsers drop sync or extensions entirely, while mainstream privacy browsers handle these features with varying setups.

Here is how the top privacy-respecting and private-by-default options stack up against your exact criteria:

1. Mozilla Firefox (with a strict privacy configuration or via forks)

• Extensions: Yes (full desktop and mobile support, including Firefox Add-ons).
• Separate Profiles: Yes (via about:profiles or profile manager, allowing completely separate extension sets, cookies, and caches).
• Encrypted Bookmark & History Sync: Yes (uses Mozilla Sync , which is end-to-end encrypted with your master account password).
• Private Aspect: While stock Firefox isn’t strictly "private-by-default" out-of-the-box (it includes telemetry that can be toggled off), it is open-source, blocks third-party trackers aggressively by default, and does not monetize your search or history data.
• Note on Forks: Hardened forks like LibreWolf strip out Mozilla Sync entirely for privacy reasons (relying on manual sync or third-party tools), making vanilla Firefox (or slightly customized Firefox configurations) the pragmatic choice if you specifically need built-in encrypted multi-device sync.

2. Brave Browser

• Extensions: Yes (supports Chrome Web Store extensions).
• Separate Profiles: Yes (supports clean, isolated local user profiles on desktop).
• Encrypted Bookmark & History Sync: Yes (uses Brave Sync , which relies on client-side zero-knowledge encryption via a sync chain code—not a cloud password—meaning Brave cannot read your synced bookmarks or history).
• Private Aspect: Highly private-by-default (blocks ads, trackers, and fingerprinting scripts out of the box), though some users have controversies regarding its built-in crypto/rewards ecosystem (which can be completely disabled in settings).
• Caveat on Profiles & Sync: Brave's sync chain links devices, but it syncs data globally to that chain rather than separating data cleanly per individual local profile across devices (i.e., Profile 1 on Device A won't cleanly map to a separate isolated Profile 1 on Device B without manual pairing workarounds).

3. Mullvad Browser / Tor Browser

• Extensions: No (extensions are intentionally blocked to prevent fingerprinting).
• Separate Profiles: No.
• Encrypted Sync: No (syncing history or bookmarks across devices destroys the anonymity model).
• Verdict: Mentioned for context—these fail your criteria because persistent cross-device syncing and extensions fundamentally compromise the threat model of high-security private browsers.

Summary Checklist

To help narrow down the ideal fit, do you prioritize out-of-the-box anti-tracking protection (like Brave) or complete open-source customizability and extension freedom (like Firefox)? Also, do you need this sync to work on mobile devices as well as desktop?

If by private you mean a browser that is privacy-oriented and supports extensions + multiple profiles + end-to-end/client-side encrypted sync of bookmarks and history, the field is surprisingly small.

1. Vivaldi — closest to your exact requirements

Vivaldi supports Chrome extensions, and each profile can have its own extensions, bookmarks, cookies, history, settings, etc.

Its Sync system can synchronize bookmarks, history, extensions, passwords, settings, tabs and more, with the synced data end-to-end encrypted using an encryption password that isn't sent to Vivaldi.

One unusual limitation: each Vivaldi profile currently needs a separate Vivaldi account to sync its profile data across devices.

Verdict: Probably the best fit if separate, isolated browser profiles are important.

2. Brave — excellent privacy + encrypted sync

Brave supports Chrome Web Store extensions and has profiles. Its Sync system synchronizes bookmarks, history and other browsing data between devices.

The important privacy feature is that Brave encrypts Sync data on the client/device, with the decryption key kept on your devices rather than available to Brave.

Brave also doesn't require a conventional cloud account for Sync; devices are connected through a Sync chain.

Verdict: I'd pick Brave if your priority is privacy + Chromium compatibility, especially if you don't need elaborate profile management.

3. Firefox — strongest alternative if you want to avoid Chromium

Firefox Sync supports bookmarks, browsing history, add-ons/extensions, settings, passwords, tabs and more. Mozilla says the synced data is encrypted so Mozilla can't read it.

Firefox also supports multiple profiles, and Mozilla's documentation specifically notes that different Firefox profiles can participate in Sync.

There is one catch: extensions and settings synchronization is currently limited to desktop Firefox; bookmarks/history can sync with mobile.

Verdict: Best choice if you want privacy, open-source software, and a non-Chromium browser, but its profile/sync behavior is less polished for this particular use case.

My ranking for your requirements

Vivaldi > Brave > Firefox

If you tell me whether you need Windows + macOS + Android + iPhone, I can narrow this down further—especially because mobile support and whether each profile can have its own independent sync account make a big difference.