What is Trezor Bridge?
Trezor Bridge is a small, trusted background application that runs on your computer and provides a secure communication channel between your Trezor hardware device and the browser (or desktop apps). It translates USB/Bluetooth messages into a format the browser can safely call via a local endpoint, while enforcing that only authorized local pages can talk to your Trezor device.
Unlike browser extensions, Bridge runs at the OS level and helps avoid many limitations imposed by browser sandboxes. It is intentionally minimal: it does not store private keys or seed phrases — those remain on the hardware device.
When do you need it?
- To use Trezor with browser-based wallets or web apps that expect a local bridge.
- To connect desktop wallet software that communicates with the Trezor over USB or Bluetooth.
- When direct WebUSB support is unavailable or blocked by the browser or OS policy.
Safe installation checklist
Follow these steps to install Bridge safely:
- Official source only: Download installers from Trezor's official website or verified documentation. Do not follow random search-result links or files from mirrors you don't trust.
- Verify signatures: If the project publishes checksums or signed releases, verify them on your system before running the installer.
- Run as normal user: Install using your regular account unless elevated privileges are required; review prompts carefully.
- Keep software updated: Bridge updates may contain security and compatibility fixes — apply them from official updates only.
How Bridge works (high level)
At runtime, Bridge listens on a local port bound to localhost. The browser or desktop app sends requests to that port; Bridge validates and forwards them to the Trezor device via USB/Bluetooth. Critical operations — such as signing transactions — are always confirmed on the Trezor device itself. That hardware confirmation is the last and strongest line of defense against compromised desktops or web pages.
Security best practices
Bridge adds convenience but does not replace hardware-level security. Follow these rules:
- Never reveal your recovery seed: Bridge, the browser, or the desktop app will never ask for your seed. If a page or prompt requests it — treat it as malicious.
- Confirm on-device: Always read and confirm transaction details on the Trezor screen before approving.
- Limit trusted apps: Only allow connections from apps and websites you trust. Revoke permissions or close the Bridge if you suspect misuse.
- Use separate browser profile: For crypto interactions, consider a dedicated browser profile without untrusted extensions to reduce attack surface.
- Keep OS patched: Local attackers rely on OS/browser vulnerabilities; keep everything updated.
Troubleshooting common issues
If Bridge is not connecting or your device is not recognized, try these steps in order:
- Ensure the Trezor device is unlocked and the screen is active.
- Restart Bridge (quit the background app and relaunch it).
- Try a different USB cable or port — prefer the original cable.
- Check for OS-level blocking (macOS permissions, Windows driver prompt, or Linux udev rules).
- Disable other applications that might claim the USB device (e.g., virtualization software or other wallet apps).
- Reboot your computer if the device still isn’t detected.
If problems persist, consult official Trezor support documentation and include diagnostic logs if requested — but never share your seed or passphrase with support.
Privacy considerations
Bridge itself does not exfiltrate private keys or transaction secrets. However, the apps and websites you connect to may learn which accounts you query or transactions you sign. If metadata privacy is a concern, consider routing traffic through privacy-preserving tooling and avoid connecting to unknown web services.
Alternatives & advanced setups
Some users prefer:
- Direct WebUSB/WebHID: Modern browsers can communicate directly with some hardware without a bridge — check compatibility and security tradeoffs.
- Dedicated desktop apps: Use well-reviewed desktop wallet software that supports the Trezor natively.
- Air-gapped workflows: For highest security, use an offline computer to prepare transactions and a connected machine for broadcasting, minimizing exposure.
FAQ
Q: Does Bridge store my recovery seed?
A: No. Seeds and private keys remain on the Trezor device.
Q: Can an attacker use Bridge to steal funds?
A: Not directly — critical signing actions require on-device confirmation. But a compromised computer/browser can trick you into approving harmful requests, so verify carefully on the device.
Q: Where to download Bridge?
A: Always follow official Trezor documentation and download pages. If in doubt, use the vendor's verified homepage or contact official support.