Trezor Bridge — Secure Connection for Your Trezor Hardware Wallet

Introduction — What is Trezor Bridge?

Trezor Bridge is a small background application that enables secure communication between your Trezor hardware wallet and web-based wallet interfaces on your computer. It acts as an intermediary that translates browser requests to the USB protocol used by the device, without exposing your private keys. In short: Bridge makes it easy and safe to use your Trezor with web apps while keeping cryptographic secrets inside the hardware wallet.

Why Trezor Bridge matters

Hardware wallets are only as useful as the software that connects to them. A secure, well-maintained bridge ensures that users aren't forced to rely on potentially risky browser extensions or loosely-supported drivers. Trezor Bridge centralizes updates, reduces compatibility problems across browsers and platforms, and provides an auditable communication layer between your machine and the device's firmware.

Key benefits

• Cross-browser compatibility — works with modern browsers without extension magic.
• Minimal attack surface — Bridge is strictly a conduit: private keys never leave the device.
• Ease of installation — installers for Windows, macOS and Linux simplify onboarding.
• Regular updates — security fixes and feature improvements are shipped independently of the web UI.

How Trezor Bridge works (technical overview)

The Bridge runs as a local service on your computer, listening on a localhost port. When a web wallet (for example, Trezor Suite or a dApp supporting Trezor) needs to sign a transaction or request device state, it sends an HTTP request to the Bridge. The Bridge then forwards the request to the Trezor device over USB using the native protocol. After the device processes the request (e.g., prompting for user confirmation and performing cryptographic operations), the Bridge sends the response back to the browser.

Security model

Important assumptions and properties:

• Device-first security: The Trezor keeps private keys inside the secure element; Bridge only relays commands and results.
• Localhost-only: Bridge listens on local network interfaces only—remote entities cannot directly call it unless they have local machine access.
• Prompt-based confirmation: Sensitive actions always require confirmation on the physical device to prevent remote unauthorized signing.

Protocols & components

Bridge uses a lightweight HTTP JSON API over localhost combined with USB HID transport. On the device side, the Trezor firmware exposes a structured API (the Trezor protocol) that accepts commands such as get public key, sign transaction, or show address. Bridge translates and forwards these commands while exposing a developer-friendly interface.

Installing Trezor Bridge (step-by-step)

Follow these steps to install Bridge on common operating systems. Always download Bridge from official sources to avoid malicious impostors.

Before you begin

• Use the official Trezor website or the official GitHub release page for installers.
• Close browser windows that might interfere with USB access during installation.
• Ensure you have backed up your recovery seed and understand recovery procedures before performing sensitive actions.

Windows

1. Download the Windows installer from the official site (links in the Resources section below).
2. Run the installer as Administrator and follow the on-screen prompts.
3. After installation, you'll usually see a Bridge icon in the system tray; the service will start automatically.
4. Open your browser and visit your web wallet. It should detect the Bridge and the Trezor device when connected.

macOS

1. Download the macOS package (.dmg) from the official source.
2. Open the disk image and drag the Bridge app into Applications.
3. On first run, macOS may ask you to grant permissions for the Bridge to access USB devices—allow them for normal operation.

Linux

There are different packages depending on distribution—use the official instructions for Debian/Ubuntu, Fedora, and Arch derivatives. In many cases, a snap or AppImage is also available for convenience.

Common issues & troubleshooting

Even with a mature tool like Bridge, users occasionally run into problems. Here are tried-and-tested fixes.

Bridge not detected by browser

• Make sure the Bridge service is running (check system tray / activity monitor / systemd service).
• Restart the browser after installing Bridge.
• Try a different USB cable or port—some cables are power-only and do not support data transfer.

Device not recognized

Unplug and replug the device. If it still fails to appear, try the device on another computer to rule out hardware issues. If the device is in bootloader mode or firmware recovery, follow official recovery instructions.

Unexpected errors during signing

• Confirm that the firmware on your Trezor is up to date—outdated firmware can cause compatibility problems.
• Clear browser cache or try an incognito/private window to rule out extensions interfering with requests.
• Temporarily disable other wallet extensions that may intercept USB or HID access, then retry.

Advanced troubleshooting

If you need logs for deeper diagnosis, Trezor Bridge and Trezor Suite can produce logs that help developers identify problems. Only share logs with trusted support channels and redact any local file paths you don't want to reveal publicly.

Security best practices

Bridge is designed to reduce risk, but your practices matter. Follow these policies to keep your crypto safe.

Always verify the site

Only connect your Trezor to sites you trust. Confirm the URL is correct and the certificate is valid. Many phishing attacks mimic wallet interfaces—double-check everything.

Keep software up to date

• Install updates for Trezor Bridge and firmware as they become available.
• Update your browser and OS—old software can have vulnerabilities that affect USB communication.

Use hardware confirmations

Never approve operations on the device unless you initiated them. The physical button confirmations on the Trezor help ensure an attacker cannot silently sign transactions.

Minimize exposure

Avoid using Bridge or signing transactions on shared or untrusted machines. Treat your Trezor like a secure appliance: connect it only to systems you control.

Advanced tips & developer notes

Programmatic access

Developers integrating Trezor devices can rely on Bridge's localhost API for standardized communication. Libraries such as the official Trezor Connect and TypeScript tools abstract the transport layer so you can focus on UX and wallet logic.

Testing and CI

In automated test environments, consider mocking the Bridge API or using emulators to simulate device responses. Avoid exposing real seeds or hardware during CI runs.

Contributing & auditing

Trezor's code and firmware are open source. Security-minded developers are encouraged to audit code, submit issues, and contribute via official GitHub repositories.

Frequently Asked Questions (FAQ)

Q: Is Trezor Bridge safe?

A: Yes — Bridge only relays messages between your browser and the hardware wallet. Private keys remain stored on the device and never transit through Bridge in plaintext. Always download Bridge from official sources.

Q: Do I need Bridge if I use Trezor Suite?

A: Trezor Suite bundles its own connectivity solutions, but Bridge may still be required for browser-based wallets or third-party dApps.

Q: Can Bridge be used remotely?

A: No — Bridge listens on localhost and is intended for local machine use. Remote access would require explicit local configuration and is not recommended.

Q: My browser still can't find the device after installing Bridge — what now?

A: Restart your browser and check that the Bridge service is running. Try another USB cable, verify permissions, and consult the official troubleshooting guides.

Q: Where can I find the installers and documentation?

A: Official installers, documentation, and source code links are included in the Resources section below. Always prefer official channels to reduce risk of malware.

Resources & official links

Below are official and authoritative resources for Trezor Bridge, firmware, developer docs, and support.

Final notes

This guide aims to give a practical, security-focused overview of Trezor Bridge. Software and best practices evolve — check the official pages above for the latest releases, advisories, and developer guidelines. If you run into trouble, use official support channels and never disclose your recovery seed to anyone.