Firefox Sync actually works

Original Article ↗ Hacker News Discussion ↗

Firefox’s cross-device Sync feature draws strong praise for reliably sharing bookmarks, passwords, tabs and settings across desktops and phones, with end-to-end encryption and even self-hosting options seen as major advantages over Chrome and Edge. Many users cite it, along with features like Multi-Account Containers, vertical tabs and robust extension vetting, as a key reason to switch to or stick with Firefox amid growing frustration with Google’s ad and tracking ecosystem. Others report sync glitches, mobile (especially iOS) rough edges, and gaps in certain web APIs, arguing that alternatives like Safari, Brave or dedicated password managers can be more stable or better aligned with their needs.

Overall sentiment on Firefox Sync

  • Many users report Firefox Sync “just works” across multiple devices and OSes, with fast tab sending and reliable syncing of bookmarks, passwords, and settings.
  • Others find it unreliable or fragile, citing corrupted bookmark databases, lost containers, or sync failures that were hard to debug.
  • Some long‑time users avoid Sync entirely, preferring manual profile copies or generic file‑sync tools.

Reliability & specific issues

  • Reported problems include:
    • Password sets suddenly shrinking across all devices (notably on Developer/Beta builds), requiring manual export/import recovery.
    • about:config tweaks, container assignments, add‑ons, and toolbar layout not consistently synced.
    • Long freezes after large history deletions.
    • Mobile limitations: no extension/setting sync on phones, separate “mobile bookmarks” folder, and awkward bookmark tags/history management.
    • Firefox for iOS described as buggy, with flaky tab and bookmark sync and bookmark ordering issues.
  • A few users say Sync “reliably fails” for them despite repeated reconnects.

Privacy, encryption, and self‑hosting

  • Firefox Sync is described as end‑to‑end encrypted: keys are derived client‑side from the account password; Mozilla stores only opaque blobs and can’t recover data if the password is lost (without recovery keys).
  • Some are still uneasy about cloud storage of history and prefer to sync only add‑ons, configs, and bookmarks.
  • Firefox’s sync and accounts servers are open source; several people self‑host them, noting mixed ease of setup and some rough edges, especially with newer Rust components.

Comparisons with other browsers’ sync

  • Chrome Sync generally works well for many, but its privacy model is criticized; enabling strong encryption requires extra steps and its UX is called “dark‑patterned.”
  • Brave, Vivaldi, Safari, and Arc are praised for solid sync in their ecosystems, though:
    • Safari is constrained to Apple IDs and platforms.
    • Brave/Vivaldi sometimes show multi‑minute delays.
    • Edge is noted for non‑E2EE browsing‑history sync.
  • Some prefer Brave or Chromium for engine compatibility but value Firefox’s privacy stance and MV3‑resistant ad‑blocking.

Beyond Sync: other Firefox draws and deal‑breakers

  • Strong positives:
    • Multi‑account containers (often cited as a “killer feature,” especially for multiple AWS/Google accounts).
    • Vertical/tree‑style tabs (Tree Style Tab, Sidebery) plus userChrome tweaks.
    • Mobile extensions like uBlock Origin on Android.
    • Recommended extensions program with manual code review.
    • Features like override‑right‑click and richer dev tools.
  • Negatives / blockers:
    • Performance stutters, high memory use, and occasional incompatibilities or missing APIs (e.g., WebSerial, WebNFC, Google Meet screen share).
    • Limited or historically restricted Android/iOS extension and automation support.
    • Annoyances around Mozilla’s marketing UX (what’s‑new pages, donation prompts).

Divergent attitudes toward sync and passwords

  • Some see full multi‑device sync (history, tabs, passwords) as essential to their workflow.
  • Others want a “dumb,” stateless browser each session and either disable sync or limit it to settings/extensions.
  • Opinions on built‑in password storage are split: several advocate dedicated managers (KeePass, Bitwarden, etc.), while others are satisfied with Firefox’s password manager but expect very high stability.