Trezor^ Bridge – Secure Your Hardware Wallet®

Introduction

This document provides a comprehensive presentation-style guide to Trezor Bridge, the desktop component that enables communication between your Trezor hardware wallet and the applications (usually web wallets or desktop apps) you use to manage your crypto assets. The content below includes conceptual explanations, installation steps for major platforms, security considerations, practical workflows, troubleshooting steps, developer notes, and an FAQ.

Intended audience: end users, security-conscious individuals, and developers integrating Trezor into applications.

What is Trezor Bridge?

Trezor Bridge is a small, local background service (daemon) that runs on your computer and acts as the bridge between:

Your Trezor hardware device (via USB)
Applications and websites running in your browser or on your desktop that need to send commands to the device

Historically, browsers limited direct USB access; Bridge provides a standardized local API endpoint which applications can call using secure protocols to interact with a connected Trezor device. When properly installed and configured, Bridge exposes a local HTTP(s) or named-pipe endpoint that client applications use to forward messages to the device.

Why is it necessary?

Trezor devices operate as secure, offline signing appliances. The host (your computer) prepares transactions and data; the Trezor device signs them after explicit user confirmation. Bridge simplifies the host-device conversation while providing OS-level compatibility and some security controls, such as restricting which origins may access the device (when using browser-connected flows).

Installation & Setup

Supported Platforms

Windows 10 and 11 (x64)
macOS (Intel & Apple Silicon)
Linux (various distributions — native packages or AppImage)

Clean Install Steps (recommended)

Download Trezor Bridge only from the official Trezor website (verify the URL and TLS certificate).
Verify the installer if a checksum or signature is provided by Trezor's site.
Run the installer and allow the application to install the background service/daemon.
Connect your Trezor device via USB. The device should show its welcome/lock screen and may require you to enter your PIN on the device for protected actions.
Open the Trezor Suite or your wallet application; the app should detect Bridge and the connected device.

Example: macOS (manual)

# Example (macOS) 1. Open the downloaded .dmg and drag Trezor Bridge to Applications. 2. Give necessary permissions in System Preferences > Security & Privacy if macOS blocks the install. 3. Start the application or let it run as a background service.

Example: Linux

Depending on distribution you may install via package or run an AppImage. Ensure udev rules for device access are in place on Linux so that non-root users can access the USB device.

Security model and best practices

The core security principle behind Trezor is that private keys never leave the hardware device. All sensitive signing occurs on the device itself after the user confirms the transaction or message on the device display. Bridge is not a vault for secrets; it's merely a communication channel.

Threats & mitigations

Malicious host software: If your computer is compromised, attackers may attempt to craft malicious transaction payloads. Mitigation: always verify transaction details on your Trezor device display — the device shows addresses and amounts to confirm.
Phishing sites: Only connect your Trezor to trusted wallet interfaces. Mitigation: use bookmarks, check TLS certificates, and prefer official wallet apps like Trezor Suite.
Compromised Bridge binaries: Mitigation: download only from official sources, verify checksums if provided, and keep Bridge updated.
USB-level attacks: Use only cables you trust. Avoid public USB chargers and hubs of unknown provenance.

Important: No party other than the user and the Trezor device should be able to produce a valid signature for your private key. That is the single most important security guarantee — verify it by checking device firmware signatures and using the device only with trusted software.

PIN, Passphrase, and Seed Safety

Use a PIN on the device to prevent unauthorized physical use. Consider using a passphrase (BIP-39 passphrase) as an optional 25th word: it creates a hidden wallet but must be used with caution — if you lose the passphrase the associated funds are effectively unrecoverable.

Using Trezor Bridge in daily workflows

Common workflows

Open your preferred wallet website or Trezor Suite.
Connect device via USB; unlock with PIN if necessary.
Compose a transaction in the host application (recipient, amount, fee).
Host sends the transaction request to Bridge; Bridge forwards to the device.
Review transaction details on the device screen carefully.
Confirm on-device to sign; the signed transaction returns to the host for broadcast.

Multi-account & multiple coins

Trezor devices support multiple cryptocurrency accounts and types. Bridge allows the host to select the coin and account path (BIP32/BIP44 derivations). Always confirm the displayed derivation/account on the device UI if your wallet supports showing it.

{ "type": "request", "command": "ethereumSignTransaction", "payload": { "path": "m/44'/60'/0'/0/0", "tx": { /* RLP fields */ } } }

When to update Bridge

Keep Bridge updated to receive security fixes and compatibility improvements. However, avoid installing unsigned or third-party builds unless you understand the implications.

Troubleshooting

Device not detected

Check USB cable and port (prefer a direct port over a hub).
Ensure Bridge is running (check system tray / background services).
Restart browser / application and re-plug device.
Check OS-level permissions (macOS security, Windows driver prompts).

Browser blocking connection

Browsers sometimes block local connections or block mixed content. If your wallet uses a web origin, ensure you allow the browser to access the local Bridge endpoint or use an official wallet integration that instructs you on how to allow access.

Bridge version conflicts

If an application expects a specific Bridge API version, upgrade Bridge or the application. In rare cases, uninstalling and reinstalling Bridge resolves prior broken installs.

Warning: Do not enter your seed phrase into any computer. Trezor will never ask you to type your full seed into a host — only directly on the device when initializing in recovery mode (and even then, type carefully and only on trusted firmware).

Best practices & practical tips

Operational security

Store your recovery seed offline and in multiple secure locations; consider using steel backups for long-term durability.
Use passphrases only if you understand the risk of loss; document your procedures in secure offline documentation.
Prefer hardware wallets for long-term storage and limit hot wallet exposure.

Software hygiene

Keep your OS and browser updated.
Use reputable antivirus and scan for malware periodically.
Prefer official Trezor Suite where possible to reduce risk of spoofed web pages.

Customizing Bridge

Most users should not modify Bridge settings. Advanced users may consult developer docs for command-line flags, logging, or advanced network setup.

Developer notes

API & integration overview

Bridge exposes a transport layer; software integration typically proceeds through a library (such as trezor-connect or platform SDKs). The host forms command messages, sends them to Bridge, which forwards to the device, and receives replies. Libraries usually abstract transport details and provide helpful higher-level functions.

Security for integrators

Validate messages returned by the device.
Ensure the host verifies device firmware versions and fingerprints if required for your threat model.
Respect origin policies and avoid unnecessarily exposing RPC endpoints over the network.

Example integration flow (pseudocode)

// Pseudocode connectToBridge(); requestPublicKey(accountPath); prepareTransaction(); sendSignRequest(txPayload); awaitDeviceConfirmation(); receiveSignedTx(); broadcastToNetwork();

FAQ

Q: Is Trezor Bridge open-source?

A: Many components of the Trezor ecosystem are open-source; check Trezor's official repositories for the latest details and code.

Q: Can Bridge access my seed?

A: No. Bridge only forwards commands to the device. Your seed (recovery phrase) is never exposed to Bridge or the host when used properly.

Q: What if I lose my device?

A: Use your recovery seed to restore funds onto a new device. If you used a passphrase, you'll need that passphrase as well to access the same hidden wallet.

Appendix — Additional resources & changelog

Changelog (example)

v1.0.0 — initial major release, USB bridging and cross-platform support.
v1.1.x — bug fixes, driver improvements for Windows and macOS notarization.
v1.2.x — security patches, improved logging, improved udev rules for Linux.

Additional resources

For official downloads, developer docs, and the latest security notices, always consult the official Trezor website and GitHub repositories.

Printable checklist

Download official Bridge from trezor.io
Install and verify version
Connect device and confirm firmware
Set PIN and back up seed securely
Use Trezor Suite or trusted wallet