browser-sync

Open-source toolset (espinosacodes) to migrate your browser logins and your active signed-in state (sessions) between browsers and machines, without losing either. Everything stays on your machine, nothing is uploaded anywhere.

macOS Firefox  ->  browser-sync  ->  Fedora Firefox (or Chrome/Brave/etc.)

Download & install

npm: command published under @espinosacodes/browser-sync.

npm install -g @espinosacodes/browser-sync

That installs the browser-sync command on macOS, Windows, or Linux (your Mac and your Fedora laptop both). Runs on Node 14+. No Python required.

Requirements (one line): Node.js 14+ on each machine.

Or run it without installing (no global install needed):

npx @espinosacodes/browser-sync --help

Or clone the source from github.com/espinosacodes/browser-sync and build:

git clone https://github.com/espinosacodes/browser-sync.git
cd browser-sync
npm install && npm run build
node dist/index.js --help

Verify the install

browser-sync selfcheck
# selfcheck OK: 3 input rows merged to 2, longest password kept, output written

If that prints OK, the tool is working. (It is tested on every release via this self-check.)

browser-sync merge firefox.csv chrome.csv -o for-fedora.csv   # saved logins
browser-sync carry --to /tmp/session-carry   # active signed-in sessions

Two commands:

• browser-sync merge moves saved logins (usernames + passwords) as CSV across Firefox / Chrome / Edge / Brave / Vivaldi / Opera / Bitwarden.
• browser-sync carry copies your "already signed in" sessions (cookies + keys) from one Firefox profile to another machine's Firefox.

Carrying "I'm already signed in" (sessions) - carry

If what you want is: on the new machine you are already signed into GitHub, Gmail, AWS, etc., exactly like on your Mac, that is cookies, and this is the command you want.

# On your Mac, with Firefox fully closed:
browser-sync carry --to /tmp/session-carry   # use --dry-run first to preview
#   -> copies cookies.sqlite, key4.db, cert9.db into /tmp/session-carry

# Move that folder to the Fedora machine (USB/email), then there:
browser-sync carry --src /tmp/session-carry --to ~/.mozilla/firefox/<profile>.default-release

cookies.sqlite holds the session data, key4.db the encryption keys, and cert9.db the certificates. They must move together. Firefox must be closed on both ends while copying.

What to expect: many sites (Google, banking, SSO) detect a new device/IP and force a fresh sign-in on first use. That is enforced by the website, not by this tool, and cannot be bypassed. Sites without that check carry over fully signed-in.

Passwords/logins are intentionally NOT moved by carry; use merge for those.

Moving saved logins (passwords) - merge

1. Export from the source browser

| Browser | Path | |--------|------| | Firefox | Menu -> Logins and Passwords -> ... (ellipsis) -> Export Logins... | | Chrome | Settings -> Autofill and passwords -> Google Password Manager -> Settings -> Export passwords | | Edge | Settings -> Profiles -> Passwords -> (three dots) -> Export passwords | | Brave / Vivaldi / Opera | Settings -> Passwords -> Export (like Chrome) | | Bitwarden | Vault -> options -> Export vault (csv) |

You get a .csv file. Keep it somewhere safe; it is your passwords in plain text.

2. Merge and clean

browser-sync merge firefox.csv -o for-linux.csv
# or combine exports from many browsers:
browser-sync merge firefox.csv chrome.csv edge.csv -o for-linux.csv
# or export for a Bitwarden vault:
browser-sync merge firefox.csv --to bitwarden -o bw.csv

It auto-detects each source (Firefox vs Chrome-family vs Bitwarden), drops empty rows, collapses duplicate logins across sources (same site + username = one entry, keeps the longest password), and writes one clean CSV.

3. Import on the target machine

Copy the CSV to the new machine, then in the target browser: Settings -> Passwords -> Import... and pick the file. Done. Firefox / Chrome / Edge / Brave / Vivaldi / Opera / Bitwarden all accept the name,url,username,password header emitted by default.

What it handles

• Firefox's extra columns (httpRealm, formActionOrigin) vs Chrome/Brave's bare name,url,username,password, vs Bitwarden's vault schema.
• Cross-browser duplicates: the same GitHub login saved in both Firefox and Chrome collapses to one row.
• Sites Google leaves bare (e.g. mail.google.com) stay usable.

Testing

The project is tested. npm run build then node dist/index.js selfcheck exercises the merge/carry logic directly against sample CSVs and temp profiles; a correct result fails the build. The legacy make selfcheck runs all three suites (the TypeScript CLI plus the Python twins).

npm run build && npm run selfcheck    # TypeScript CLI (primary, ships to npm)
make selfcheck                        # all suites: TS CLI + Python twins

These run automatically on npm publish (via prepublishOnly), so every published version is verified.

Project layout

package.json       npm package (@espinosacodes/browser-sync), TypeScript build
cli/index.ts       the entire CLI in TypeScript (merge + carry), zero runtime deps
dist/index.js      compiled output shipped to npm (generated by `npm run build`)
browser_sync.py    legacy Python twin of `merge`
carry_session.py   legacy Python twin of `carry`
extension/         optional browser extension that captures NEW logins as you type
                   them (cannot reach already-saved passwords), see extension/README
LICENSE            MIT

The package is written in TypeScript; npm run build compiles cli/index.ts to dist/index.js (npm runs the compiled JS).

Security notes

• This tool never sends data off your machine. It reads and writes local files.
• Handle exported CSV files carefully; they contain plaintext passwords.
• The optional extension keeps captured logins in local browser storage only; no cloud by default.

Roadmap (espinosacodes)

• [x] Core CSV migration + dedupe across browsers and OSes
• [x] Bitwarden export format
• [x] Carry active sessions (cookies) between machines
• [ ] GUI (drag-and-drop a CSV, pick target, get clean file)
• [ ] Optional Google OAuth to sync a captured-vault file across your machines
• [ ] Native Firefox extension that wraps export/import in one click

License

MIT (c) 2026 espinosacodes. Open source, free to fork.