Trezor Bridge — The Secure Gateway to Your Hardware Wallet®

What is Trezor Bridge?

Trezor Bridge is a small, local service that runs on your computer to enable secure communication between your Trezor hardware wallet (Model One, Model T, and successors) and web or desktop interfaces such as Trezor Suite or compatible third-party wallets. It acts as a carefully designed translator and proxy that abstracts low-level USB and HID differences across operating systems, exposing a simple, stable HTTPS-based local endpoint (typically on 127.0.0.1) that trusted applications can use to enumerate devices, request addresses, and submit signing operations.

In short: Bridge is the bridge — it makes a browser or desktop app able to talk to your hardware wallet reliably while keeping the cryptographic authority inside the device itself. The core goal is to remove platform complexity while preserving the highest security guarantees offered by the Trezor hardware.

Why it exists

Browsers and operating systems provide varying levels of USB and WebUSB support. Historically, differences in drivers and security models made browser integration brittle across platforms. Bridge provides:

• Cross-platform consistency: one small, signed package that works on Windows, macOS, and Linux.
• Local secure endpoint: web apps connect to https://127.0.0.1 to interact with devices while user confirmations remain on-device.
• Driver simplification: eliminates the need for end users to install native drivers or manually manage USB access.
• Clear user consent model: sensitive operations still require explicit confirmation on the physical device screen.

Download & Install: step-by-step

Always download Trezor Bridge from the official Trezor website or a verified repository. Avoid installing packages linked from unsolicited emails or posts.

Windows

1. Open your browser and navigate to the official Trezor downloads page: trezor.io/trezor-suite (or the Bridge-specific download section).
2. Download the Windows Bridge installer (an .exe file). Prefer the signed MSI/EXE offered on the official site.
3. Run the installer and follow on-screen prompts. Windows may request administrator privileges.
4. After installation, Bridge runs as a background service and exposes a local HTTPS endpoint. Open Trezor Suite (desktop or web) and it should detect Bridge automatically.

macOS

1. Download the macOS Bridge installer (usually a .dmg or signed package).
2. Open the installer and drag the Bridge app to Applications if required. You may need to allow the app in System Preferences → Security & Privacy.
3. Run Bridge; it will start a local service. Trezor Suite (or supported web pages) will detect the Bridge endpoint and prompt for device connections.

Linux (AppImage / packages)

1. Choose the AppImage or your distribution package (where available).
2. Mark AppImage as executable chmod +x trezor-bridge.AppImage and run it, or install via your package manager if an official repo is provided.
3. Bridge will run as a user service and expose the local HTTPS endpoint for web apps to use.

Verifying authenticity

When available, verify the developer signature or checksum provided on the official Trezor site. This extra step rules out tampered installers. If you’re using package managers or distribution repositories, prefer official or well-known community-maintained sources.

Using Bridge with Trezor Suite & web apps

Bridge is invisible most of the time: after installation it runs and waits for trusted web apps or the Suite to connect. Typical user flow:

1. Open Trezor Suite (desktop) or go to suite.trezor.io in your browser.
2. Click “Connect” or “Unlock device.” The web app connects to the Bridge endpoint and enumerates attached Trezor devices.
3. Select the device in the app. The app may request address information, public keys, or a signing operation.
4. The Trezor device displays the full details on-screen. You verify and physically approve each signing request (addresses, amounts, smart contract data).

Important: Bridge never has access to private keys. All sensitive cryptographic operations happen inside the Trezor device. Bridge merely forwards messages between the app and the device.

Security & privacy considerations

Trezor Bridge is designed with a security-first mindset, but user behavior and environment matter. Below are recommended practices to keep the attack surface minimal.

Download only from official sources

Always use the official website or verified distribution channels. Do not install Bridge from third-party mirrors or links received via unsolicited messages. If in doubt, type the official domain manually or use a bookmarked link.

Keep Bridge and firmware updated

Updates fix bugs and patch vulnerabilities. Keep Bridge, Trezor Suite, and your device firmware up-to-date. Firmware updates are signed and require on-device confirmation to proceed.

Local-only binding

Bridge listens on a localhost address by default and does not expose a route to the wider network. That said, treat your host machine as trusted during a Bridge session. Avoid connecting unknown or untrusted browser pages while the wallet is connected.

Browser & extension hygiene

Limit the number of active browser extensions, especially those that interact with or intercept web requests (ad-blockers, privacy add-ons). If a web flow fails, temporary extension suspension can help diagnose whether an extension is interfering with Bridge connections.

On-device verification is the last line of defense

Even with Bridge in the middle, the device screen remains the authoritative source. Always verify addresses, amounts, and contract details on the physical device before approving. Never confirm anything on the device without understanding what you are signing.

Troubleshooting: common problems & fixes

Bridge is deliberately simple, but occasional problems happen. Below are common issues and pragmatic fixes.

Bridge not running / not detected

• Check if the Bridge service is running: on Windows look in the system tray; on macOS check Activity Monitor; on Linux check running processes.
• Restart the Bridge service and the browser or Suite.
• Reboot the machine if the service fails to start after reinstall.

Browser cannot connect to local endpoint

• Confirm the browser allows local HTTPS calls to 127.0.0.1. Some privacy settings or enterprise policies block localhost connections.
• Temporarily disable strict content-blocking or privacy extensions and retry.
• If the browser shows certificate warnings, restart Bridge so it can regenerate its local certificate and accept the local exception when prompted.

Device not showing up

• Check physical USB cable and port — use the official cable and avoid unpowered hubs.
• Ensure the device is unlocked (enter PIN) before Suite attempts operations.
• Try a different USB cable/port or another computer to isolate the issue.

Permission / driver conflicts

On some setups older USB drivers or third-party software (e.g., virtualization or USB debugging tools) can interfere. Temporarily disabling such tools or uninstalling conflicting drivers can resolve issues. On Linux, ensure necessary udev rules are present for device access.

Developer & advanced usage notes

Developers integrating with Trezor Bridge should follow strict safety and UX guidelines.

API & integration

Bridge exposes a documented API (JSON-RPC over HTTPS) that allows enumeration of attached devices, retrieval of public keys/addresses, and forwarding of signing requests. When building integrations:

• Always require explicit user action and on-device confirmation for any signing operation.
• Show clear human-readable transaction details in the app before sending commands to the device.
• Handle device disconnection and error states gracefully — never retain stale state indicating a device is connected when it is not.

Automation caution

While the API enables scripting and automation for testing, production automation that sidesteps explicit user confirmations defeats the security model and is discouraged. If automation is necessary (e.g., for CI tests), restrict it to safe testnets and ephemeral keys.

Testing & testnets

Use testnet funds when developing or testing. Ensure tools clearly distinguish mainnet vs testnet and prevent accidental mainnet signing in test flows.

Privacy considerations

Bridge itself does not transmit your keys or seed. However, certain metadata may be visible to local applications (e.g., account xpubs). Consider these privacy steps:

• Run Bridge only when needed and close it when not in use.
• Use dedicated machines or isolated browser profiles for high-value operations if you require stronger isolation.
• Prefer applications that minimize metadata collection and allow local-only operation when possible.

FAQ — short answers

Do I always need Bridge?

For most browser flows and some desktop scenarios, Bridge simplifies connectivity and is recommended. Some desktop apps may use native USB methods but Bridge is the cross-platform official option.

Is Bridge safe to run?

Yes — when downloaded from official sources and kept up to date. Bridge does not have access to private keys and only forwards requests to the hardware device.

What if Bridge stops after an OS update?

Restart Bridge and the browser. If issues persist, reinstall the latest Bridge package from the official Trezor site and check OS permission prompts.

Can I run Bridge on a headless server?

Bridge is intended for local interactive use with a connected device. Running it on a remote/hosted server breaks the assumption of local physical access and is not recommended for mainnet signing workflows.

Final checklist & best practices

• Download Trezor Bridge only from trezor.io or official channels.
• Verify checksums or installer signatures when provided.
• Keep Bridge, Trezor Suite, and device firmware updated.
• Always verify transaction details on the physical Trezor device before approving.
• Limit browser extensions and avoid visiting unknown sites while your wallet is connected.
• Consider a dedicated secure environment (VM or separate machine) for high-value operations.

Trezor Bridge is a small but critical piece of the secure wallet ecosystem — it makes modern browser and desktop experiences possible while anchoring cryptographic trust in the hardware. Treat it as a trusted local service, maintain good software hygiene, and verify everything on-device.