Trezor Bridge is a lightweight application that creates a secure local communication channel between a Trezor hardware wallet and browser-based wallet interfaces (such as Trezor Suite or web-based dapps). It replaces older browser plugins by running as a native local service that handles USB communication, device discovery, and message routing while minimizing the exposure of private keys and reducing attack surface. This presentation walks through why Bridge exists, how it works, common installation scenarios, security best practices, and troubleshooting steps for common issues.
Browsers intentionally limit raw USB access for security reasons. Bridge runs outside the browser and provides a controlled, authenticated channel between your browser UI and the device. This keeps cryptographic operations strictly on the device and prevents web pages from directly accessing USB endpoints or private key material. Bridge therefore acts as a secure translator and gatekeeper.
Trezor Bridge runs as a local process and exposes a localhost HTTP(s) API that the browser can call. When a user interacts with a web wallet (for example, connecting to Trezor Suite or a dApp that supports Trezor), the site asks the browser to connect; the browser forwards the request to Bridge which enumerates devices via the OS USB stack and routes messages to the appropriate Trezor device. All sensitive cryptographic operations—key derivation, transaction signing, PIN handling—are performed on the device itself.
Bridge supports multiple transports (USB HID, WebUSB wrappers or direct OS USB APIs depending on platform). Transport security relies on OS-level device permissions and Bridge's local-only API endpoint. Because Bridge listens on localhost only, remote exploitation requires local host compromise; nevertheless, following principle of least privilege and good host hygiene is critical.
Bridge works with modern browsers (Chrome, Edge, Firefox with certain preferences, Brave) and with Trezor Suite (desktop or web). Platform builds are provided for Windows (installer), macOS (PKG), and Linux (AppImage / deb / rpm). Automatic updates are released periodically; users should keep Bridge up to date to benefit from security and compatibility fixes.
Download the official Bridge installer for your platform from Trezor's download pages and follow the platform-specific installation steps. After installation, Bridge typically runs in the background and registers a localhost endpoint. Some browsers will prompt for permission when connecting to your Trezor for the first time.
Because Bridge communicates over localhost, rarely does it require inbound firewall permissions. If a host firewall blocks localhost loopback calls, temporarily allow Bridge or create a rule for the local endpoint. On corporate-managed devices, security policies might prevent installation; coordinate with IT to ensure safe deployment.
Bridge minimizes risk by restricting sensitive operations to the Trezor device. Nevertheless, users must practice good host security because Bridge runs locally and can be invoked by browser pages. The following considerations reduce risk and increase overall safety.
Trezor devices require PIN entry and confirmation on the device for critical actions. Even if Bridge or the browser is compromised, an attacker cannot sign transactions without access to the unlocked device and user confirmation on the device's screen and buttons.
If a browser or Trezor Suite can't find Bridge: verify Bridge is running (check system tray / activity monitor), restart the browser, reinstall Bridge, and ensure USB cable is data-capable. Try another USB port and avoid USB hubs when diagnosing connectivity problems.
Bridge produces local logs that can be consulted for debugging. On many systems logs are accessible via the Bridge menu or a log file in the user profile. Collect logs and device debug output when contacting support or filing a bug report.
Linux users may need udev rules for USB access. Installing Bridge packages or following the official instructions usually creates the correct rules. If not, consult the Trezor knowledge base for distro-specific steps.
Desktop versions of Trezor Suite typically communicate directly with the device without Bridge, while the web-based Suite or browser integrations use Bridge. Check the Suite download page and release notes for the current recommended setup.
Much of Trezor's tooling is open-source and available in public repositories. Review the official repositories for source code, build instructions, and community discussion. Open-source status allows independent audits and increases transparency.
Install updates when they're released. Security and compatibility fixes are the most important reason to keep Bridge recent. Automatic update mechanisms exist for some platforms; otherwise check the official download page periodically.
Below are useful official pages for downloads, docs, security advisories, and support. Always verify the domain (trezor.io or github.com/trezor) before downloading.
Developers integrating Trezor should consult the official API docs, example repositories on GitHub, and use the testnet/simulators when developing. Ensure you follow secure integration patterns and request only the minimum permissions you need from users.
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$ ps aux | grep trezord
# or on Windows use Task Manager and search for Trezor Bridge processes