Install · about 2 minutes

Download atbridge.ai

Two pieces: the atbridge.ai app (a small command-line tool) and the Thunderbird add-on. Install both, connect them, done — on macOS, Linux, or Windows.

Choose your OS

Easiest — no terminal. Install the add-on (Step 2 below) and the setup wizard opens automatically: it installs the atbridge.ai app in one click, then walks you through activating your plan and connecting your AI. Steps 1, 3 & 4 are the manual alternative.

On Linux, follow all four steps below. If your Thunderbird is not a Snap/Flatpak install, the one-click path works too — install the add-on and follow the wizard. On Snap/Flatpak (confined) Thunderbird, enable the local-bridge (loopback) fallback so the helper can connect — turn it on in the first-run wizard's Step 1 (Enable local bridge) or in atbridge Settings → Local bridge (Snap/Flatpak).

Before you start

Thunderbird 128 or newer — check via Help → About Thunderbird. Get Thunderbird if you don't have it.
One mail account in Thunderbird — with "Keep messages on this computer" enabled (on by default for most). We verify it in the last step.

Install the app

Run one command. It downloads the atbridge app for your platform (a single small executable — no dependencies), registers it with your Thunderbird profile, and hands the add-on to Thunderbird — nothing else is touched.

$ curl -fsSL https://atbridge.ai/install.sh | sh

PS> irm https://atbridge.ai/install.ps1 | iex

Run in PowerShell. No admin rights needed — everything installs per-user.

Verify it worked: atbridge --version should print a version number.

Add the Thunderbird add-on

The add-on is a .xpi for Thunderbird 128+. Download it, then install it from file inside Thunderbird.

atbridge.ai for Thunderbird

Thunderbird add-on · .xpi · Thunderbird 128+

Download the add-on

⏳ The add-on goes live at launch. Everything else on this page works now — come back for this file, or ask us for early access.

Then, in Thunderbird:

Open Thunderbird and click the gear icon in the bottom-left corner (Settings).
In Settings, in the menu at the bottom (just to the right of the Settings gear) click Add-ons and Themes.
To the right of the Manage your Extensions header, click the gear icon (Tools for all add-ons).
In that menu, choose Install Add-on From File, then pick the downloaded .xpi (the name carries its version) and confirm the permission prompt.
You'll see atbridge.ai in the add-ons list with a green check.

Connect & activate

Back in your terminal (PowerShell on Windows), connect the app to Thunderbird:

$ atbridge bridge install

Then activate your plan — auto-detect walks your Thunderbird accounts and picks the right one:

$ atbridge license activate

Bought Personal or Pro? Give your Thunderbird account email at the prompt. Just trying it out? Press Enter to start the 14-day free trial.

Using Snap or Flatpak Thunderbird?

The confined app connects over the local bridge instead — run this in place of bridge install:

$ atbridge bridge service install && atbridge bridge service start

Auto-detect can't read your accounts under confinement, so activate with your license key — find it in your account:

$ atbridge license activate --email you@example.com --key <your-key>

Verify

$ atbridge license status --pretty

You want to see your plan, status ok, and Local storage enabled ✓. If that last row says DISABLED, in Thunderbird open Account Settings → Synchronization & Storage, tick "Keep messages for this account on this computer", then click Download Now.

Full install guide →The same steps with screenshots, gotchas, and a "stuck?" form. Connect your AI →Point Claude Desktop, Cursor, or any agent at atbridge.ai. Stuck? Email us →contact@atbridge.ai — a human reads every message.