Overview
What is Trezor Bridge?
Trezor Bridge is lightweight software that runs on your desktop to ensure secure, reliable communication between your Trezor hardware wallet and browser-based or desktop wallet applications. It acts as a local intermediary that translates USB/HID messages from the Trezor device into a secure, standardized protocol that web applications like Trezor Suite or third-party wallets can use. This removes the need for direct, low-level USB access in the browser and adds an additional layer of compatibility and security for modern operating systems.
Why it exists
Browsers restrict direct hardware access for safety reasons. Trezor Bridge fills the gap by providing a trusted local service that exposes a secure API to authorized wallet software. This keeps sensitive operations isolated to the hardware wallet while giving applications a dependable channel for transaction signing, device setup, and firmware management.
At-a-glance
- Local bridge between device and apps
- Improves cross-platform compatibility
- Reduces direct USB handling inside browsers
Security Model
Design principles
Trezor Bridge is designed with minimal trust assumptions: the hardware wallet retains all critical secrets (private keys), the bridge only forwards encrypted or authorized commands, and user confirmation on the device remains the authoritative approval for sensitive actions. Bridge itself does not hold or transmit private keys; it merely facilitates command transport and device discovery.
Threats and mitigations
Typical threats include malicious local software attempting to intercept traffic, man-in-the-middle attacks, and social-engineering attempts. Mitigations include code signing for Bridge installers, TLS-like local transport protections, strict origin checks, and clear UI prompts on the Trezor device for all critical approvals. Users should always verify firmware authenticity and only install Bridge from official channels.
Best practice
Keep Bridge updated via official sources, avoid installing unknown browser extensions that request hardware access, and always confirm transaction details on the Trezor screen rather than relying solely on your computer.
Installation & Setup
Supported platforms
Trezor Bridge supports major desktop operating systems (Windows, macOS, Linux). Installation is quick and includes an installer that adds a small background service. After installing, browser-based apps detect your device via the local Bridge API and prompt you to connect your device.
Step-by-step setup
- Download the Bridge installer from an official source.
- Run the installer and follow on-screen instructions (macOS may request security permissions).
- Restart the browser if necessary and open Trezor Suite or your preferred wallet.
- When prompted, unlock your device and confirm connection on the Trezor screen.
Troubleshooting tips
If Bridge cannot see your device, try a different USB cable, check OS permissions, or reinstall Bridge. Ensure the Trezor firmware is up to date and that no other application is claiming exclusive access to the USB port.
How Bridge Works (Technical)
Architecture
At a high level, Bridge runs as a local HTTP(S) service, exposing endpoints that wallet software queries. The service communicates with the Trezor device over USB using the appropriate device drivers and translates messages into a JSON-RPC-like API for applications. This keeps the hardware-specific code in the Bridge binary while keeping application code simple and cross-platform.
Message flow
When a wallet needs a signature, it constructs a request and sends it to the Bridge endpoint. Bridge forwards the request to the Trezor device, waits for the user to confirm the action on the device display, and then relays the signed response back to the wallet app. The wallet never sees private keys; only signed payloads are returned.
Compatibility
Because the Bridge abstracts the USB layer, new Trezor models and firmware updates can be supported by updating Bridge rather than requiring changes in every wallet application. This extensible model reduces fragmentation and simplifies developer workflows.
Privacy Considerations
What Bridge can and cannot see
Bridge can see metadata about the commands (for example: that a signing operation occurred), but it does not gain access to private keys or hidden wallet seeds. Bridge is not a telemetry collector by default; users should review settings, but the core transport is focused on local device communication rather than cloud collection.
User data handling
Official Bridge builds minimize data collection. When using third-party wallets in conjunction with Bridge, check each application's privacy policy since applications may collect usage data separately from the Bridge process.
Reducing exposure
Use Bridge only with trusted applications and avoid sharing logs publicly without redacting sensitive fields. If privacy is paramount, use air-gapped workflows for cold-storage assets and avoid connecting hardware to online hosts for long-term storage operations.
Developer Notes
Integrating with Bridge
Developers building wallet integrations can interact with Bridge via its documented API endpoints. Use the official libraries and SDKs where possible to ensure correct message formatting and error handling. Respect user prompts and surface clear UX that instructs users to confirm details on the device.
API example
Testing and sandbox
Test integrations with both emulator and real devices. Emulators can speed development, but final verification should use hardware to ensure user confirmations and UI flows behave as expected.
User Workflows
Common actions
From onboarding and seed generation to sending transactions and firmware upgrades, Bridge helps orchestrate interactions while keeping the user in control. Typical workflows include device initialization, signing transactions, verifying addresses, and upgrading firmware through Trezor Suite or supported apps.
Security-centric habits
Always verify receiving addresses on your Trezor device screen, never type your seed on a connected computer, and double-check the URL and certificate of any web-based wallet before connecting Bridge. These habits significantly reduce attack surface and social-engineering risks.
Edge cases
If Bridge installation fails due to OS restrictions (for example, corporate-managed machines), consult your IT team or use a personal machine for sensitive transactions. For power users, consider using a live USB OS to minimize host-side persistent threats.
Links & Resources
Official resources for downloads, support, security advisories, and documentation. Each link is styled for clarity.
Note: Always verify the domain and certificate when visiting these links. Avoid installing Bridge from unofficial mirrors.
Accessibility
The Bridge installer includes accessibility-friendly prompts and supports common screen readers. Documentation covers keyboard shortcuts and alternative flows for users who cannot use a mouse or touchscreen during setup.
Enterprise considerations
When deploying in managed environments, administrators should use signed installers and distribution tools to ensure only approved Bridge builds are deployed. Consider network segmentation and host hardening for endpoints that will manage keys at scale.
Backup workflows
Bridge does not manage backups. Users should follow hardware wallet best practices: generate and securely store the seed phrase offline, use metal backups if available, and never share seed material digitally.
Future directions
Ongoing improvements include tighter OS integration, expanded protocol features for multi-device support, and additional privacy-preserving transport options. The community and developer feedback drive these enhancements.
Appendix: Common Commands & CLI
Command samples
Below are illustrative examples only — exact CLI flags change between releases. Use official docs when scripting Bridge operations.
Logging
Bridge can produce logs for troubleshooting. Only share logs with trusted support personnel and scrub any identifiers if privacy is a concern.
Support flow
If you need help, collect logs, environment details (OS, Bridge version), and a step-by-step description of the issue before contacting official support to expedite resolution.