What is Trezor Bridge?
Trezor Bridge is the small, focused application that enables secure communication between a Trezor hardware wallet and applications running in your browser or on your desktop. Its role is intentionally narrow: it provides a reliable USB-to-app bridge so that wallet hardware never exposes private keys to the network or browser environment.
By acting as a mediator, the Bridge handles transport, device discovery, and secure messaging. The design philosophy favours transparency, minimal attack surface, and ease of use: install the Bridge once, and multiple wallet frontends — desktop apps or websites — can safely talk to your Trezor device.
Key Benefits
Bridge isolates USB access into a single trusted component.
Available for Windows, macOS and Linux with a consistent interface.
Runs with only the privileges required for secure communication with the device.
Detects and lists connected devices for quick access in wallet apps.
How it works (brief)
When you open a compatible wallet interface, the frontend requests a connection to Trezor Bridge (usually via an API exposed on a local port). Bridge enumerates connected Trezor devices, negotiates a secure transport channel, and forwards JSON-based commands to the device. The device itself signs transactions and performs cryptographic operations; sensitive key material never leaves the hardware.
Typical interaction life-cycle:
- Install Bridge on your machine and launch it.
- Open a wallet frontend (web or desktop) that supports Trezor.
- Grant access to the device when prompted.
- Approve each operation on the hardware device screen.
Quick install & usage
Installation steps are intentionally compact — Bridge is a lightweight helper app.
- Download the appropriate installer for your OS and run it.
- Start Bridge (on many OSs it starts automatically after installation).
- Open your wallet frontend (for example, a web app) and choose "Connect Trezor".
- When asked, confirm connection on your device and complete the action from the frontend.
Many frontends communicate with Bridge on a local port (for example 127.0.0.1:21325), but the exact port and method are managed automatically by the Bridge application.
Security considerations
Security depends on a chain of trust: the Trezor hardware, the Bridge, and your wallet frontend. Important practices include:
- Only download Bridge from the official Trezor website or verified distribution channels.
- Keep Bridge up to date so you receive security fixes promptly.
- Verify the fingerprint or checksum for installers where provided.
- Always confirm transactions on the device screen — never approve an action you don't recognize.
Because Bridge is only a transport layer, it does not store seeds or private keys — the Trezor device stores them securely.
Compatibility & troubleshooting
Bridge is compatible with the major operating systems and works with most web-based and desktop wallet frontends that support Trezor. If your device is not detected:
- Ensure Bridge is running (check system tray / menu bar).
- Try unplugging and replugging the Trezor device into a different USB port.
- Restart the browser or the wallet application.
- On macOS and new Windows systems, grant the requested permissions to allow local connections.
FAQ
Q: Does Bridge hold my keys?
A: No — private keys remain on the hardware device.
Q: Can multiple apps use Bridge simultaneously?
A: Yes — Bridge multiplexes connections so different frontends can access the device concurrently as needed.
Q: Is Bridge open source?
A: Components of the Trezor ecosystem are open; consult the project’s repository for exact licensing and source information.