What is Trezor Bridge?
Trezor Bridge is a lightweight desktop helper application that enables communication between a Trezor hardware wallet and your web browser or desktop wallet applications. When you connect a Trezor device to your computer, Bridge acts like a secure local server that forwards encrypted commands between the Trezor device and client software (for example, a browser-based wallet or the Trezor Suite desktop app).
Why Bridge exists
Modern browsers restrict direct access to USB devices for security reasons. Trezor Bridge provides a stable, cross-platform way to expose your Trezor to trusted client applications without compromising security:
- Standardizes communication across Windows, macOS and Linux.
- Provides automatic updates and certificate handling.
- Isolates USB interactions in a small, audited program rather than within browser code.
Key features
- Cross-platform support: runs on major desktop operating systems.
- Secure forwarding: pass-through of encrypted APDU commands between clients and the device.
- Automatic detection: detects when Trezor devices are connected or disconnected.
- Small footprint: lightweight and focused; it does not manage or store keys.
How it works (simple)
When installed, Trezor Bridge starts a local background service (a small web server bound to a localhost port). Wallet apps communicate with that service using HTTPS (local only). The Bridge then talks to the physical Trezor over USB and relays responses back to the wallet. All sensitive operations remain on the hardware device; Bridge only relays messages.
Installing Trezor Bridge (general steps)
- Download the official installer from the official Trezor website or the Trezor Suite app (always use the vendor's official page).
- Run the installer and follow platform prompts (macOS: allow kernel extensions or system access when requested; Windows: run as administrator if prompted).
- Plug in your Trezor device and allow the browser or desktop app to connect when prompted.
- If required, accept any security dialogs and confirm the device actions on the physical Trezor screen.
Security considerations
Bridge is a facilitator only — it does not hold your keys. Best practices:
- Always download Bridge from the official source.
- Verify installer signatures if a vendor-provided signature is available.
- Keep Bridge and your Trezor firmware up to date to receive security patches.
- Do not share your recovery seed with any software; recoveries should be performed only on an offline device when possible.
Troubleshooting common issues
Device not detected
- Check the USB cable (use a data cable, not charge-only).
- Try a different USB port or a powered hub.
- Restart Bridge (quit the app or service and relaunch).
- On Windows, check Device Manager for driver warnings; reinstall Bridge as admin.
Browser prompts and permissions
Some browsers may ask you to allow the connection to the Bridge or present certificate warnings the first time. Make sure you are using a trusted wallet and accept only when you recognize the request.
Developer notes (brief)
For integrators, Bridge exposes a local JSON over HTTPS API to which client apps send commands. The protocol is intentionally simple — clients convert user actions into APDU commands that the Trezor hardware understands. Always follow the official developer documentation and use packaged client libraries when available.
FAQ
Does Bridge store my seed?
No. Bridge is only a communication relay. Your private keys and seed remain on-device.
Can I use Trezor without Bridge?
Some desktop apps talk directly to the device using native USB drivers; however, Bridge simplifies browser-based integration and is recommended for web wallet usage.
Final thoughts
Trezor Bridge plays a small but important role: it creates a secure, well-defined bridge between your hardware wallet and the software you use. As with any security tool, the safest results come from following vendor guidance, keeping software up to date, and validating sources before download.