What is Trezor Bridge?

Trezor Bridge is a small background application that allows communication between your Trezor hardware wallet (the physical device) and web applications (such as the Trezor Suite or supported third-party wallets) via USB (or in some cases, WebUSB). Bridge acts as a local proxy that translates browser requests into commands the Trezor device understands, and vice versa. Unlike browser-only solutions, Bridge runs on the host system, providing a persistent and controlled channel for device discovery, firmware operations, signing requests, and secure transport of cryptographic commands.

Why does Bridge exist?

Web browsers intentionally limit direct access to raw USB and other low-level system resources for security reasons. Bridge fills this gap by creating a trusted local intermediary. This design reduces the need for browser extensions while allowing the Trezor team to implement device-specific features, compatibility patches, and platform integrations. Bridge also centralizes versioning and upgrade pathways for device communication logic.

High-level responsibilities of Bridge

Device enumeration and discovery across USB backends.
Forwarding application protocol messages to and from the Trezor device.
Providing a secure, signed channel for firmware updates and integrity checks.
Maintaining user prompts and device lock states in coordination with Trezor Suite.
Logging and telemetry (optional and user-controlled) used to debug compatibility issues.

Supported platforms

Official Bridge builds are made for Windows, macOS, and Linux. The installer packages and runtime artifacts differ by platform (e.g., DMG for macOS, EXE/MSI for Windows, DEB/RPM/AppImage for Linux distributions). Check official release notes for the exact supported versions and system requirements.

Summary of user flow

Install Trezor Bridge on your computer.
Open a compatible web wallet or Trezor Suite in your browser.
Connect your Trezor device by USB.
The browser communicates with Bridge to enumerate and authenticate the device.
You confirm actions physically on the Trezor device (PIN, passphrase, confirmations).
Signed transactions or resulting data return to the browser application.

A note on security model

Bridge is intentionally a minimal attack surface. It does not hold private keys or secrets — those remain protected within the Trezor hardware. Bridge's responsibility is routing, integrity checks, and controlled exposure of device capabilities to authorized web clients. Users should only run official Bridge releases and verify checksums/signatures when available.

Installing Trezor Bridge

Installing Bridge is straightforward: download the official installer for your operating system from the Trezor website, run the installer, then optionally restart your browser. Many modern browsers will detect Bridge automatically after installation; however, some combinations may require restarting the browser or granting explicit permissions.

Windows installation steps

1) Download the Windows installer (EXE or MSI) from the official Trezor site. 2) Run the installer with administrative privileges. 3) Follow on-screen prompts. 4) Reboot the computer if the installer asks (driver-level installs may require it). 5) Open a compatible browser and connect the device.

macOS installation steps

1) Download the DMG (or PKG) from the official site. 2) Open the DMG and drag the Bridge app to the Applications folder (or run the PKG). 3) Confirm any security prompts in macOS system preferences (if Gatekeeper blocks unsigned components you may need to allow them). 4) Launch Bridge or open a browser and connect your device.

Linux installation notes

Linux packaging varies. You may find DEB or RPM files for popular distributions, or an AppImage for a portable install. Some distributions require udev rules to be installed so non-root users can access USB Trezor devices. When provided in releases, install the udev rules file into /etc/udev/rules.d/ and reload the udev configuration:

sudo cp 99-trezor.rules /etc/udev/rules.d/
sudo udevadm control --reload-rules
sudo udevadm trigger

Common pitfalls during installation

Old Bridge versions conflict: uninstall older versions before installing a new release.
Antivirus or system blockers: temporarily disable or allow Bridge through security tools if installation is blocked.
Browser caching: after install, restart the browser to ensure the WebSocket/localhost registrations update properly.
Permissions on Linux: ensure you have udev rules and appropriate group membership to access USB devices.

Verifying your installation

You can verify Bridge is running by checking system processes for a "trezord" or "trezor-bridge" entry, or by opening Trezor Suite which typically surfaces a confirmation when Bridge responds successfully.

Using Bridge with Trezor Suite and web wallets

Once Bridge is installed, open Trezor Suite (desktop or web) or any compatible wallet. Most wallets detect Bridge via local host IPC endpoints. You'll typically be prompted to connect your device, enter your PIN (if set), and complete confirmations on the device screen.

Typical user actions

Creating a new wallet (seed generation occurs on the device).
Restoring a wallet from recovery seed (via device).
Signing transactions for sending funds.
Approving firmware updates for the device (requires explicit user confirmation).
Using passphrase or hidden wallet features as supported by Trezor models.

Passphrase handling

Bridge may be involved in passing passphrase-related prompts between the browser and the device, but the passphrase itself should ideally never be transmitted or stored by Bridge. Instead, passphrase entry is performed either on the device or within a local client that respects the secure entry flow. Users should understand the difference between an optional "hidden wallet" and the standard wallet, and follow best practices for passphrase storage and input.

Browser compatibility

Most major browsers (Chrome, Edge, Firefox, Brave) can work with Bridge. Some browser privacy settings or extensions that block localhost requests or WebSocket connections may interfere; temporarily relaxing these settings for trusted sites is a common troubleshooting step.

Multiple wallets or multi-window sessions

Bridge is designed to handle concurrent requests, but some user workflows (e.g., running multiple wallet tabs simultaneously) can confuse device state. If unexpected behavior occurs, close other wallet tabs and try again, or disconnect and reconnect the device.

Developer note: permitted origins

For security, Bridge restricts which web origins can access devices without explicit user permission. When developing web integrations, follow the official libraries and manifest requirements. Trezor also publishes client libraries and documentation for JavaScript integration that show examples for requesting device access and handling device lifecycle events.

Troubleshooting common issues

This section catalogs frequent Bridge problems and practical resolutions. Most issues relate to version mismatches, driver conflicts, browser blocking, or ephemeral USB connectivity problems.

Bridge not detected by browser

Ensure Bridge is running (check system tray / process list).
Restart your browser and reconnect the device.
Temporarily disable browser extensions that block localhost or WebSocket traffic.
Verify that the installed Bridge version is the latest official release.

Device not showing up or recognized incorrectly

Confirm cable integrity and USB port health — some USB-C cables only support power and not data. Try a different cable and port. On Windows, update USB drivers if prompted. On Linux, ensure udev rules are present and your user account has permission to access USB devices.

Firmware update problems

Firmware updates require an uninterrupted connection and explicit confirmation on the device. If an update stalls:

Do not unplug the device until instructed by the update dialog.
Restart the computer if Bridge appears unresponsive, then retry the update.
If a device becomes unresponsive during update, consult official recovery instructions — typically, reflash procedures exist but must be followed exactly.

Permission errors in browser console

When a web app logs permission or origin errors, it usually indicates Bridge is refusing the origin or the browser blocked the request. Confirm the wallet's origin is authorized and try to grant permission when the browser prompts. For development, check documentation on allowed origins.

Logging and diagnostic mode

Many Bridge builds include a verbose or debug logging mode that can be enabled for diagnostics. Logs help Trezor support pinpoint issues without exposing secrets. If asked by support, export logs and redact any personal information before sharing.

Security best practices

Even though Bridge is a facilitator and not a secret keeper, users should adopt strong operational security:

Always verify sources

Download Bridge only from official Trezor channels. Verify checksums or digital signatures when provided. Avoid third-party downloads.

Keep software up to date

Periodically check for Bridge updates and upgrade Trezor Suite and firmware when new stable releases are announced. Updates often include security patches and compatibility fixes.

Minimize background apps

Avoid running unknown background utilities that might hook USB or intercept localhost connections. Use reputable security software and configure it to allow Bridge.

Use physical confirmations

Trezor device confirmations (taps, PIN entry, and on-device verification of transaction details) are the primary security mechanism. Never approve requests you don't explicitly recognize on the device screen.

Advanced privacy considerations

If privacy is a priority, combine Bridge usage with privacy-preserving wallet software and avoid reusing addresses. Use coin control features where available, and consider secondary privacy tools such as coinjoin or mixing services only as appropriate and compliant with local law.

Developer integration & APIs

Developers building integrations with Trezor use official libraries and protocols. Bridge exposes local endpoints and a message transport that libraries wrap for convenience. The recommended approach is to use the maintained client SDKs which implement transport, permission handling, and device compatibility.

Transport protocols

Bridge abstracts different transports (raw HID, WebUSB, and possibly others) so the higher-level interfaces can focus on devi