Trezor Bridge is the communication layer that connects Trezor hardware wallets to a user’s computer and to web-based cryptocurrency applications. It runs locally and acts as a secure, lightweight intermediary between a Trezor device and browser interfaces, enabling safe transaction signing, firmware updates, and account management while keeping private keys on the device.
At its core, Bridge detects connected Trezor devices and exposes a minimal, well-defined API for applications to call. Browser-based wallets and sites interact with Bridge through standardized messages that request actions such as fetching public addresses, preparing transactions, or initiating firmware installation. Crucially, cryptographic operations such as signing remain on the hardware; Bridge only transports signed messages between the device and the requesting application.
Bridge is cross-platform and designed to be lightweight. It supports the major desktop operating systems and typically installs as a small background service or native process. Installation is straightforward: users run a provided installer or package and the Bridge service starts automatically. Once running, it integrates with supported browsers and wallet software so that device interactions are seamless for the end user.
Security is central to Bridge’s architecture. Connections between web applications and a Trezor device require explicit approval on the physical device screen, preventing unauthorized remote usage. Bridge uses encrypted local channels to protect communication from other local processes. It minimizes exposed endpoints, performs origin checks for browser requests, and aims to present a small attack surface. When combined with the hardware confirmation model, this design helps ensure an attacker cannot remotely extract private keys or silently sign transactions.
From a user experience standpoint, Bridge reduces friction. It auto-detects device models, supports multiple simultaneous connections, and surfaces clear status messages for operations like firmware updates or transaction signing. For developers, Bridge provides a versioned API and reference examples, making it easier to integrate hardware-wallet support into web wallets and services. Versioning helps maintain compatibility across firmware updates and Bridge releases.
Bridge also solves browser compatibility issues. Not all browsers provide uniform access to USB devices or the same quality of WebUSB support. By running as a local native application, Bridge offers a consistent API surface regardless of browser differences and expands accessibility for users on browsers without full native USB support.
Privacy is a key consideration. Because Bridge runs locally, routine operations do not relay user data or transaction details to remote servers. Only features that require network access—such as fetching firmware updates or checking versions—communicate with official servers, and those actions are explicit and transparent. The hardware wallet model ensures private keys are never exposed to the network: Bridge simply transports signed payloads and status messages.
For troubleshooting, Bridge includes diagnostic and logging options for advanced users and support teams. Common fixes include restarting the Bridge service, trying a different USB cable or port, and ensuring the browser is configured to allow local connections. On Linux, checking USB permissions and udev rules is often required. Thorough release notes and community support channels typically accompany Bridge releases to help users resolve issues quickly.
Developers benefit from a straightforward integration model. Bridge exposes RPC-style calls and follows semantic versioning so clients can detect supported capabilities. This allows web wallets to negotiate features with a connected device and maintain compatibility across software versions. Many open-source wallets integrate with Bridge, enabling users to combine the security of hardware keys with the convenience of web interfaces.
In summary, Trezor Bridge is a reliable companion for securely connecting Trezor hardware to desktop and web-based applications. By operating locally, minimizing network exposure, and requiring physical confirmation for sensitive actions, Bridge helps balance strong security with a polished user experience. Users should still follow best practices—keep recovery seeds offline, verify addresses displayed on the device before signing, and install Bridge only from trusted sources—to ensure a safe setup.