Trezor Bridge — The Secure Gateway to Your Hardware Wallet®

Overview — what is Trezor Bridge?

Trezor Bridge is a small, secure local application (a background service/daemon) that enables communication between your Trezor hardware wallet and desktop applications or web services. It acts as a controlled translator: the hardware wallet uses a USB protocol to talk to the host computer, and Bridge exposes a safe, standardized interface so apps (like Trezor Suite or compatible web wallets) can send requests to the device.

Without Bridge, browsers and desktop apps would need low-level USB access to communicate with the device, which is less consistent and more error-prone across operating systems and browser versions. Bridge simplifies this by providing a stable, well-tested interface and handling permissioning, device enumeration, and minor protocol differences across platforms.

Why Bridge matters for security and usability

Security boundary: Bridge keeps the privileged USB interactions isolated in a small, auditable native program while user-facing apps operate at a higher level. This reduces attack surface and centralizes updates for secure communication.
Cross-platform compatibility: One Bridge binary per OS reduces variations developers must handle, improving reliability on Windows, macOS, and Linux.
Automatic updates: When installed from official channels, Bridge receives updates that include security fixes and protocol improvements without requiring users to update every third-party application that supports Trezor.
Simpler developer experience: Developers call a consistent API rather than managing USB drivers or dealing with browser-specific quirks.

Note: Bridge does not, and cannot, access or export your private keys or recovery seed. All sensitive operations (signing transactions, revealing private keys, confirming addresses) are performed on the Trezor device itself and require physical confirmation.

How Trezor Bridge works — technical components

At a high level, Bridge consists of the following components:

Local service / daemon

Runs in the background and listens for requests from client apps over a local HTTP or WebSocket interface. It enumerates connected Trezor devices and forwards safe, validated requests to the device.

Client API

Client libraries (or web pages through connectors) talk to Bridge using a small, well-documented protocol. This keeps developer code simpler and avoids reimplementing USB stack logic.

Device firmware

The Trezor device has firmware that implements the cryptographic operations and UX flows. Bridge never executes these operations — it only forwards messages and displays device status when requested.

Security checks

Bridge performs sanity checks on messages and manages access control (which app or browser context requested an operation). It also displays device state information back to the client so software can show accurate information to the user.

Installing Trezor Bridge — step-by-step

Before installing, always verify you’re downloading Bridge from the official Trezor domain or the official Trezor Suite installer. Do not install Bridge or related software from unknown or third-party download mirrors.

System requirements

Windows 10 or later, macOS 10.14 (Mojave) or later, or a modern Linux distribution.
A standard USB-A or USB-C port (use the cable provided with your Trezor).
Administrator privileges to install system services/drivers on some platforms.

Windows

Download the latest Bridge installer (MSI/EXE) from the official Trezor downloads page.
Run the installer and follow prompts. If Windows asks for driver permission, accept only if the installer is from the official source.
After installation, Bridge usually starts automatically and an icon may appear in your system tray.
Open Trezor Suite or a supported web wallet; it should detect the connected device through Bridge.

macOS

Download the macOS installer (DMG) from the official Trezor downloads page.
Open the DMG and drag the Bridge app to /Applications.
If macOS blocks the app because it’s from an unidentified developer, open System Preferences > Security & Privacy and allow the app explicitly after verifying the source.
Launch the app; it will run in the background and be accessible to apps that request access.

Linux

Install the provided package for your distribution (DEB, RPM) or follow the official instructions for manual installation.
Confirm Bridge is running as a user service. You may need to add udev rules or grant appropriate permissions so your user can access USB devices without root.
Restart your browser or desktop apps after installation if necessary.

If you prefer not to run a local Bridge service, some platforms offer browser-native WebUSB support for Trezor devices. WebUSB bypasses Bridge but has different compatibility characteristics and may require more manual permissioning. For most users, Bridge provides the most stable experience.

Security & privacy considerations

Bridge is designed with security and minimalism in mind. Important points to remember:

Bridge never stores your private keys or recovery seed. All cryptographic operations occur inside the Trezor device. Bridge only passes data required to ask the device to perform an operation.
Local-only communication: Bridge exposes a local interface on your machine — it does not open remote network ports by default. It cannot be used as a remote gateway unless explicitly configured by the user.
Permission model: When a web page or app requests access to your device, the host application (often your browser) will ask for permission. Always verify the domain and context requesting device access.
Updates: Keep Bridge and Trezor firmware up to date. Updates include important security fixes and compatibility improvements.

Privacy note: Bridge transmits minimal metadata required for operation (device model, firmware version, request types). Official Bridge builds do not send your addresses or transaction details to external servers. If you are using a third-party Bridge build or a modified client, review its source and behavior carefully.

Troubleshooting common issues

Device not detected

Ensure the Trezor is connected via a known-good USB cable and try a different port.
Restart Bridge (quit the app/service and relaunch) and then reopen Trezor Suite or your browser.
On Windows, confirm drivers were installed successfully. Re-run the installer if needed.
On Linux, ensure correct udev rules are present so your user can access USB devices (commonly provided in the Bridge package).

Browser says “No bridge detected” or cannot access device

Make sure Bridge is running (check system tray / background services) and that your browser was restarted after installation.
Confirm you haven’t blocked the Bridge’s local origin in browser settings or via a firewall.
If using WebUSB instead of Bridge, ensure the browser supports WebUSB and that you granted permission.

Bridge installation fails

Confirm you downloaded the correct installer for your OS.
Run the installer with administrative privileges if prompted.
Temporarily disable aggressive antivirus software that may block unsigned installers — but only do this after verifying the installer’s authenticity.

Bridge crashes or exhibits unexpected behavior

Check for Bridge updates and install the latest version.
Review log files (if you are comfortable) and capture the error message to share with official support. Logs usually contain helpful information about USB enumeration or permission errors.
Reboot your system if Bridge hangs after many device plug/unplug events.

When contacting support, provide the Bridge version, OS, browser version (if applicable), and a short description of what you tried. Do not share your recovery seed or any private keys.

Advanced topics — developers & power users

Using Bridge programmatically

Developers can integrate Trezor support by using official client libraries that communicate with Bridge. These libraries abstract the message format and provide helpers for device discovery, firmware checks, and user flows.

Testing and diagnostics

Bridge includes diagnostics endpoints and verbose logging modes that can help during troubleshooting. Use these in a development environment and avoid sending logs containing sensitive device state to public forums.
Automated test suites exist for many client libraries; these tests can be run against a known-good Bridge build and a test device or simulator.

Alternative flows: WebUSB vs Bridge

Some browsers offer WebUSB support that allows web pages to talk to a Trezor device without Bridge. While convenient, WebUSB:

May not be available on all browsers or OS combinations.
Requires explicit permissions per-site and per-session.
Has browser-specific UX and permission prompts that differ from Bridge behavior.

For most developers targeting the broadest set of users, supporting Bridge as the primary integration path ensures the most reliable, secure, and consistent experience.

Best practices for end users

Install only official Bridge builds. Verify download sources and checksums if provided.
Keep software up to date. Update Bridge, Trezor Suite, and device firmware when official updates are available.
Limit exposure: Connect your Trezor only to trusted computers and networks. Avoid public or shared machines for signing transactions.
Confirm everything on-device. Always verify addresses, amounts, and recipients on the Trezor screen before approving transactions.
Understand passphrase usage. If you use a passphrase (hidden wallet), treat it like an additional secret: never store it in plain text or online.

Reminder: Official support will never ask for your recovery seed. If a support request asks for your seed, it’s a scam. When in doubt, contact support through verified channels only.

FAQ

Does Bridge send my transaction history to Trezor?

No. Bridge is a local application and does not collect or transmit your transaction history to Trezor. Any metadata sent externally would typically be related to update checks or optional telemetry, and official builds make that behavior transparent.

Can I run Bridge on a headless server or remote machine?

Bridge is primarily intended as a local desktop service. Running Bridge on headless or remote machines is technically possible but requires careful network configuration (e.g., tunneling) and significantly increases the risk profile. For most users, keeping the device and Bridge local to a trusted machine is recommended.

What if Bridge is no longer maintained?

Bridge is backed by the Trezor team and is a core part of the supported ecosystem. If that ever changes, the community and official channels would provide migration guidance. Always rely on official announcements for major architecture or tooling changes.

Resources & further reading

Before following a link, always verify the domain and ensure you’re on an official Trezor page to avoid phishing. If a link seems unexpected, navigate directly from the main Trezor website.

Conclusion — Bridge as a practical, secure connector

Trezor Bridge plays a central role in making hardware wallets accessible, reliable, and secure on desktop systems. It reduces fragmentation for developers, simplifies the user experience, and maintains a clear security boundary between the host computer and your Trezor device.

For typical users, installing and updating Bridge from official sources and following the security best practices listed here will deliver a smooth, low-risk experience when managing cryptocurrency with a Trezor device.