Trezor Bridge — The Secure Gateway to Your Hardware Wallet

Why Bridge exists

• Browser security: Modern browsers limit direct USB access to web pages; Bridge provides a controlled intermediary for communication.
• Compatibility: Works across browsers and operating systems without complex driver installs.
• User experience: Avoids intrusive browser extensions and provides a unified connection model for apps.

How Bridge secures your connection

Bridge itself is not a wallet — it simply forwards messages between your apps and the device. The actual security boundary is the Trezor hardware. Private keys and signing operations always occur on the device; Bridge cannot access keys or sign transactions. Its security features include:

• Local-only: Bridge listens on localhost (127.0.0.1) and doesn't expose a public network endpoint by default.
• Origin checks: The Trezor firmware and host libraries enforce that signing must be confirmed on the physical device; web origins requesting sensitive operations are visible and displayed to the user.
• Minimal privileges: Bridge only handles USB and IPC; it does not store private keys or seed phrases.

Installation & setup (quick)

1. Download Trezor Bridge from the official Trezor website — always verify you're on the correct domain.
2. Run the installer for your OS. On first run, Bridge will create a local service that listens for app connections.
3. Open your browser or Trezor Suite; when a site requests access, Bridge will mediate the connection and your device will prompt for physical confirmation.

Note: some Linux distributions require udev rules for USB access — the installer typically guides you through enabling them, or documentation contains commands to add the correct rules.

Developer integration (high level)

Developers interact with Bridge through a JSON-RPC style API provided by the Trezor Connect library or directly via HTTP endpoints exposed by Bridge. Typical steps:

• Include trezor-connect in your web app to abstract communications.
• Request user permission to connect; prompt them to connect a device and confirm the operation on the Trezor screen.
• Handle responses and errors gracefully — never assume a device is present or will respond immediately.

// Example (pseudo)
TrezorConnect.getFeatures().then(features => {
  // show device model, firmware version, and capabilities
}).catch(err => console.error('Trezor error', err));

Important for devs: keep user privacy in mind. Do not request more permissions than necessary and explain why each operation is needed when prompting users.

Troubleshooting common issues

• Bridge not running: Check system tray / menu bar for the Bridge icon, or run the service manually from the applications menu.
• Browser can't see device: Ensure the device is connected via USB, unlocked, and the browser has permission. Try a different USB cable — many failures are caused by charge-only cables.
• Conflicting drivers: On Windows, old drivers from third-party tools can block access. Use Device Manager to remove conflicting drivers and reinstall Bridge.
• Linux permissions: Confirm udev rules are installed (usually a package adds them), and that your user is in the plugdev group if required.

Best practices & safety checklist

• Download Bridge only from the official Trezor site and verify checksums when provided.
• Keep Bridge and Trezor firmware updated regularly, but for cold-storage devices consider delaying non-critical updates until you've validated them.
• Use passphrase support on the device to add a second factor for hidden wallets; Bridge will forward operations but cannot bypass device confirmation screens.
• When working with web apps, confirm the site origin shown on your Trezor device matches the app before approving sensitive operations.

Privacy considerations

Bridge does not collect analytics by default. However, applications using Trezor Connect or other libraries may optionally log usage for debugging. If you're privacy-focused:

• Prefer desktop Suite or air-gapped signing where possible.
• Avoid entering your recovery seed into any software — Bridge never needs your seed to operate.
• Use Tor or other network-level privacy tools alongside Suite for reduced metadata leakage when interacting with online services.

Advanced: headless & CI use

For advanced automation (e.g., CI pipelines or headless servers) you can run Bridge and script interactions with Trezor Connect. This is powerful but risky: NEVER store recovery seeds on CI, and limit signing operations to controlled, auditable contexts. Consider hardware security policies and human approval steps for production signing.

FAQ

• Q: Is Bridge required? A: For many browser apps, yes — it provides the necessary bridge between web pages and USB.
• Q: Can Bridge sign transactions? A: No — signing always occurs on the device. Bridge only relays signing requests to the device and responses back to the app.
• Q: Is Bridge safe to install on a shared computer? A: It runs as a local service; shared computers introduce risk if other users can interact with the service. Use dedicated machines for high-value keys.