Trezor Bridge® Guide

Secure Connection for Trezor Hardware Wallet®

1. Overview of Trezor Bridge

Trezor Bridge® acts as an intermediary communication layer between your web browser and the Trezor hardware wallet. It ensures that commands, transactions, and signatures are transported securely without exposing sensitive data to malicious actors. Unlike direct USB-host access, Bridge establishes a secure, authenticated channel. This is crucial because modern browser security policies restrict direct hardware access for safety. Bridge allows web-based wallets or interfaces (such as Trezor Suite or web clients) to discover, talk, and manage your device reliably.

Why is Bridge necessary?

Web browsers no longer permit arbitrary USB access to devices. Bridge solves this by acting as a trusted local server on your machine. It implements a secure tunnel, validating that each request truly comes from your browser and is intended for your Trezor wallet. This ensures the integrity and confidentiality of all communications.

Security architecture

Bridge employs TLS or local cryptographic authentication to prevent man-in-the-middle attacks. Each session is ephemeral and scoped only to the active connection. The Bridge binary is small, minimal, and digitally signed by the Trezor team to avoid tampering. It also uses origin checking (i.e., which website is requesting actions) to avoid cross-site abuse.

Supported platforms

Trezor Bridge is available for Windows, macOS, and Linux. It supports both ARM and x86 architectures and can run in the background when installed, automatically starting when needed by a browser.

2. Installing Trezor Bridge

Download the installer

To begin, visit the official Trezor website and download the Bridge installer matching your operating system. Always ensure you download from the official domain to avoid counterfeit or malicious versions.

Steps for Windows

1. Run the downloaded `.exe` file.
2. Accept the license agreement.
3. Allow the installer to add firewall or security exceptions if prompted.
4. Finish the installation; Bridge will launch automatically in the background.

Steps for macOS & Linux

For macOS, open the `.dmg` installer, drag Bridge to the Applications folder. For Linux, use the `.deb` or `.rpm` package or run the AppImage. Then grant necessary permissions or use `chmod +x`. On Ubuntu, you might need `sudo apt install ./trezor-bridge*.deb`.

3. Configuration & Permissions

Firewall & Network Settings

Bridge communicates over localhost (127.0.0.1) on a designated port. Ensure your firewall or antivirus doesn’t block this loopback traffic. It never contacts outside servers by default.

Browser Integration

Once Bridge is running, your browser must request permission. On first use, the browser will prompt: “Allow this website to access your Trezor device through Bridge?” Always verify the domain and only allow for trustworthy services.

Updating Bridge

The Trezor team periodically issues updates to Bridge. When an update is available, you'll receive prompts or notifications. Always apply updates promptly to patch any vulnerabilities or compatibility issues.

4. Connecting Your Trezor Device

Establish connection via browser

With Bridge installed and running, plug in your Trezor hardware wallet via USB (or USB-C). The browser interface (Trezor Suite or a web client) will ask to “Connect device.” Approve the request, and the browser will instruct Bridge to open a secure channel.

Authentication & Session Handling

After connection, you must enter your PIN or confirm actions on your device’s screen. Bridge never sees your PIN, seed words, or private keys — it merely passes encrypted messages back and forth. When you finish, always click “Disconnect” to cleanly close the session.

Possible connection issues

- **“Device not detected”**: restart Bridge or your browser.
- **“Permission denied”**: ensure you allowed the domain.
- **Conflicting drivers**: uninstall old Trezor drivers.
- **Stale Bridge version**: upgrade to latest build.

Best practices for seamless connection

Always keep Bridge and your browser up to date. Use official cable and USB ports. Avoid hubs or splitters. And after each session, properly disconnect your device to avoid stale locks.

5. Frequently Asked Questions (FAQs)

Q1: Does Bridge see my private keys or seed?

No. Trezor Bridge acts purely as a communication conduit. It does not have access to your private keys, PIN, or recovery seed. All sensitive operations are handled on the device itself.

Q2: Why does my browser ask for permission every time?

Browser security mandates that each website explicitly requests access to hardware devices. This prevents rogue websites from silently accessing your wallet. Always verify requests before granting permission.

Q3: Can I use Bridge without internet access?

Yes. Trezor Bridge only communicates locally (via 127.0.0.1). It does not rely on internet connectivity for core operations, making it suitable for offline or air-gapped workflows.

Q4: My device is not recognized after installing Bridge — what can I do?

Steps you can take: 1. Restart your browser (or full system).
2. Check that Bridge is running (system tray or background).
3. Reconnect your Trezor and ensure the cable is functional.
4. Update Bridge to the latest version.
5. If on Linux, check USB permissions and udev rules.

Q5: Is it safe to keep Bridge running all the time?

Yes, generally. Bridge is lightweight and listens only on your local machine. It neither connects outward nor listens to external addresses by default. But if you’re extra security-conscious, you may launch it on demand when you need it.