What is Trezor Bridge?
At its core, Trezor Bridge is a small background application that mediates communications between your browser or desktop wallet and the Trezor device. It exposes a secure API endpoint locally and translates requests into USB/HID commands that the device understands. Because signing operations and recovery seed handling happen only on the hardware device, Bridge acts as a guardian — facilitating commands while never exposing private keys.
How it works (high level)
When you connect a Trezor to your computer and open a compatible wallet interface, the interface makes requests to the local Bridge service. Bridge handles authentication, ensures only permitted origins can interact with the hardware, and forwards user-approved actions to the device. The device displays confirmation prompts and signs transactions on-device. Once signed, Bridge relays safe, signed payloads back to the calling application.
Install & setup
Bridge is available for Windows, macOS, and Linux. Installation is simple: download the appropriate installer, run it, and the service will register itself on your system. After installation, when you first connect a device, your browser or desktop wallet will detect it and prompt you to allow interactions. Official installers and checksums are available from the official start page and the downloads section below.
Security & privacy
Security is the primary goal of Bridge. It uses local-only communication: Bridge listens on localhost and never transmits device data externally. Permission prompts require explicit user consent for each session, and malicious websites cannot access the device without your approval. Bridge also isolates different origins to prevent cross-site access. For optimum privacy, keep Bridge updated via official channels and avoid installing third-party plugins that interact with USB devices.
Best practices
- Download Bridge only from official sources and verify checksums.
- Keep your Bridge and Trezor firmware up to date via the official firmware channel.
- Grant device access only to trusted websites and applications.
- Use browser profiles or a dedicated browsing session when interacting with large sums.
- Disable unused browser extensions when performing sensitive operations.
Developer notes
Developers can integrate with Bridge using its local HTTP/WebSocket API. Standard libraries and client SDKs wrap common flows like device enumeration, seed generation, and transaction signing. For desktop integrations, native integrations can also use the HID layer directly, but using Bridge simplifies cross-platform compatibility. Reference implementations, API docs, and examples are linked in the developer section below.
Integration examples
Common integration patterns include: connecting a web-based wallet to sign transactions, offering a view-only wallet by importing xpubs, using Bridge for multisig workflows, and integrating with exchange or custodial systems for offline signing. Many open-source wallets provide example code that demonstrates best practices for user prompts and error handling.
Troubleshooting
If your device is not detected, try these steps: ensure Bridge is running (system tray / menu bar), reconnect the device or try a different USB cable/port, restart the browser, and verify that no other application is grabbing exclusive access to the USB device. On Windows, check driver permissions and Windows Security dialogs. If you see persistent errors, consult the support page and provide logs when requested.
FAQ
Is Bridge required? For modern browsers and many desktop apps, Bridge is the standard, user-friendly way to enable access. Some advanced integrations can communicate directly over USB but Bridge simplifies the process for most users.
Is Bridge safe? Yes — when installed from official sources and used with trusted sites. Bridge operates locally and requires explicit user confirmation for sensitive actions.
Advanced & enterprise usage
In enterprise contexts, Bridge can be deployed and managed centrally. IT teams can implement policies around allowed applications and maintain consistent Bridge versions across fleets. For high-security environments, consider using dedicated signing stations and strict physical access controls. Consult the enterprise docs and developer resources for guidance on automated testing and CI integration.
Conclusion
Trezor Bridge provides a pragmatic balance between security and usability. By keeping cryptographic operations inside the hardware and offering a consistent local API, it enables rich wallet experiences without compromising the core security model. Whether you're a casual user or a developer, following the best practices in this guide will help you maintain a secure workflow.
Next steps: download Bridge, verify installers, and explore the developer examples if you plan to integrate your application.