Trezor® Bridge — Secure Connection for Your Trezor®

Overview — What is Trezor® Bridge?

Trezor® Bridge is a lightweight connectivity application designed to facilitate secure communications between Trezor hardware wallets (such as Trezor One and Trezor Model T) and client applications — including web wallets, desktop wallets, and developer tools. The Bridge acts as a local, authenticated relay: it exposes a controlled HTTP/IPC endpoint on localhost that trusted applications use to send JSON-based commands. The Bridge forwards those commands to the Trezor device over USB (or WebUSB where supported) and returns signed responses to the calling application.

In short: Bridge keeps the low-level device communication in one signed, auditable binary and ensures that private keys and signing occur only on the hardware device itself.

Why Bridge exists

• Consistency: Provides a uniform connection layer across multiple operating systems and browsers.
• Security: Centralizes access control and minimizes the number of components that need elevated USB permissions.
• Compatibility: Enables support for a broad ecosystem of wallets and decentralized applications that need hardware-backed signing.
• Developer convenience: Offers a stable API surface for SDKs like trezor-connect, assisting rapid integration.

Core benefits & features

When used correctly, Trezor® Bridge delivers a secure and convenient user experience while preserving the core security property of the Trezor device: private keys remain on the device and every sensitive operation requires explicit user confirmation on the device's screen and buttons.

Installation & setup (Windows, macOS, Linux)

Installing Trezor® Bridge is straightforward but differs slightly across operating systems. Below are step-by-step instructions and important notes to ensure a smooth and secure installation.

Windows

1. Download the official Windows installer from the verified source. Prefer the main website or signed release archives.
2. Before running the installer, verify the file checksum or digital signature where available.
3. Run the installer and grant the requested permissions — Bridge will install a background service and register a localhost endpoint.
4. After installation, plug in your Trezor device and open your preferred wallet or browser. Grant permissions when the browser prompts for USB/local access.

Note: If your organization uses strict security controls, IT teams may need to whitelist the Bridge installer and allow the background service to run.

macOS

1. Download the DMG and mount it.
2. Drag the Bridge application to /Applications and launch it.
3. macOS will prompt for USB access and may show security dialogs — approve them for proper operation.
4. Open your wallet or Suite and connect the device.

Linux

1. Obtain the appropriate package (.deb, .rpm, or AppImage) for your distribution.
2. Install via your package manager (e.g., sudo dpkg -i trezor-bridge.deb).
3. Ensure udev rules are installed so regular users can access USB devices without root.
4. Start or restart the Bridge daemon, then connect your device.

Tip: Trezor Suite bundles connectivity for many users — if you prefer a single application, use Suite which avoids separate Bridge installation on some systems.

Security model — what Bridge protects (and doesn't)

Understanding Bridge's role in the overall threat model is essential to using your Trezor device securely. Bridge is deliberately minimal: it centralizes connectivity while relying on the device for all security-sensitive operations.

Protections offered by Bridge

• Device isolation: Keeps low-level device interactions contained within a signed binary, reducing the need for ad-hoc kernel drivers.
• Origin validation: Supports checks that help client libraries determine which page or app initiated a request.
• Out-of-band confirmation: Ensures every transaction or sensitive action is displayed and confirmed on the physical device.

Limitations — what Bridge does not solve

• Host compromise: If the computer running Bridge is infected with malware capable of intercepting clipboard contents, screen images, or network traffic, Bridge cannot fully protect the user.
• Social engineering: Bridge cannot prevent a user from being tricked into approving a malicious transaction if they do not carefully check details on the device.
• Supply chain risks: Installing tampered Bridge binaries from unofficial sources exposes users to risk; always verify downloads.

In practice, secure use of Trezor devices combines Bridge with a careful user workflow: verify addresses on-device, keep recovery phrases offline, and maintain a clean host environment.

Developer integration & recommended practices

If you're a developer integrating Trezor into an application, use established libraries (for example, trezor-connect) and follow a secure integration pattern. The Bridge API is JSON/RPC-like and intended to be consumed by high-level SDKs rather than directly by ad-hoc code.

Recommended integration flow

1. Use official SDKs to handle device discovery, session establishment, and message formatting.
2. Perform strict origin checking — always present clear context to the user before requesting signatures.
3. Design UX that shows human-readable transaction details and guides the user to verify them on the device's screen.
4. Handle errors gracefully: device disconnects, firmware update prompts, and user rejections should not leave transactions in indeterminate states.

Security tips for developers

• Do not log sensitive data like full recovery seeds or private keys. Log only high-level events useful for debugging.
• When possible, instruct users to verify checksums for downloaded Bridge binaries and provide links to official resources.
• Offer clear instructions for users on how to verify addresses and transaction details on their Trezor device.

Common user workflows

Below are practical, step-by-step workflows for the tasks most users perform when their Trezor device is connected via Bridge.

Adding an account

1. Install or open your wallet application (web wallet or Trezor Suite) after Bridge is running.
2. Connect your Trezor device to the computer and unlock it with your PIN.
3. In the wallet interface, choose "Add account" and select the desired coin or token.
4. The wallet queries the device for public addresses; confirm on-device if prompted.
5. Once added, the wallet will display balances and transaction history.

Sending crypto

1. In your wallet, construct a transaction (enter recipient, amount, optional memo).
2. Review the transaction in the wallet UI and click "Send".
3. Trezor Bridge forwards the signing request to the device; the device will show the exact address and amount.
4. Carefully verify the on-device details and approve with the device buttons.
5. The signed transaction is returned to the wallet and broadcast to the network.

Performing firmware updates

Firmware updates may be required to patch security issues or add new functionality. Always follow official instructions:

1. Make sure you have your recovery seed securely stored before updating.
2. Use Trezor Suite or the official update mechanism in a trusted browser session.
3. Follow on-screen prompts and confirm steps on the device itself.

Troubleshooting — common issues & fixes

Most connectivity problems are resolvable with a few standard checks. Use the checklist below to quickly diagnose and fix common Bridge-related problems.

Bridge not running or not detected

• Verify that the Bridge service is running: check the system tray (Windows), menu bar (macOS), or system process list (Linux).
• Restart the Bridge service and the browser/wallet application.
• Reboot your computer if the issue persists — sometimes stale OS USB states need a full restart.

Browser prompts or permission errors

• Modern browsers may present permission dialogs for WebUSB/localhost access — ensure you approve requests from trusted origins only.
• Clear browser cache or reset permissions for localhost if a stale permission state prevents connection.

Device disconnects randomly

• Try a different, high-quality USB cable and a different USB port (preferably a back-panel port on desktops).
• Disable any USB power-saving features in your OS that may suspend the port.
• Test the device on another machine to isolate whether the problem is with the device or the host.

Still stuck?

If you cannot resolve the issue, gather logs from Bridge (if available) and consult official support channels. Do not share recovery seeds or private keys — legitimate support never asks for them.

Frequently asked questions

Do I always need Bridge to use my Trezor?

Not always. Trezor Suite bundles necessary connectivity so some users never need to install a separate Bridge binary. Web-based integrations may require Bridge or leverage WebUSB depending on the browser. Bridge ensures consistent behavior across platforms.

Is Bridge safe to run?

Yes, when obtained from official sources and kept up to date. Bridge is a focused local service and does not handle sensitive secrets. Maintain standard host security hygiene (OS updates, antivirus, minimal untrusted software) to preserve overall safety.

Can multiple apps use Bridge simultaneously?

Typically, only one client should actively communicate with the device at a time to avoid race conditions. Well-behaved applications handle connection lifecycle events (connect/disconnect) cleanly and release the device when not in use.

Best practices & security checklist

1. Always download Bridge from the verified official source and verify checksums/signatures when available.
2. Confirm transaction details on the physical Trezor device before approving any signing operation.
3. Store recovery seeds offline in a secure physical location; never type them into a computer or web form.
4. Keep your host OS and antivirus updated and avoid installing untrusted browser extensions or software.
5. Prefer Trezor Suite for an integrated experience if you are unsure about manual Bridge installation.

Conclusion — practical safety and convenience

Trezor® Bridge is a practical and secure tool that simplifies the connection between your computer and your Trezor hardware wallet. It centralizes the connectivity logic, reduces friction for users and developers, and preserves the critical security property that private keys never leave the device. However, Bridge is one component in a broader security posture: safe usage depends on verified downloads, careful on-device verification of transactions, secure storage of recovery seeds, and a healthy, uncompromised host environment.

When combined with good operational habits — verify downloads, confirm transactions on-device, and treat your recovery phrase as the single most sensitive secret — Bridge helps deliver a user-friendly experience without trading away the security guarantees provided by hardware wallets.