What is Trezor Bridge and why you need it
Trezor Bridge acts as an intermediary between a Trezor device and applications running in the browser. Historically, web apps needed direct access to USB devices using WebUSB, which is not uniformly supported across all browsers and platforms. Bridge provides a consistent, secure channel by exposing a local HTTP/WebSocket API that web pages can use to detect and talk to Trezor devices via Trezor Connect. It is deliberately limited in scope and runs locally on your machine — it does not expose your device to the internet.
Download links & packages
Always download Trezor Bridge from the official Trezor site or your platform vendor. Typical packages include a Windows `.exe` installer, a macOS `.dmg` or signed installer, and Linux `.deb`/`.rpm` or AppImage options. After downloading, verify the checksum and signature where provided to confirm authenticity (see verification section below).
Installation & first-run
Installation is straightforward: run the installer for your platform, grant permissions when prompted, and Bridge will install as a background service. On first run it will start automatically and listen on a local port (e.g., http://127.0.0.1:21325 by default). Web apps that implement Trezor Connect will detect the running Bridge and prompt you to connect your device. If the Bridge is not running, web apps usually show a helpful message linking to this download page.
Verifying the download
To ensure you downloaded an authentic installer, verify the checksum and — if available — the PGP signature. Below are example commands for common platforms.
# macOS / Linux: compute SHA256 shasum -a 256 bridge-installer.pkg # Windows (PowerShell): Get-FileHash -Algorithm SHA256 .\trezor-bridge-setup.exe # GPG signature verify (if .sig provided) gpg --keyserver keyserver.ubuntu.com --recv-keys <TrezorPublicKeyID> gpg --verify trezor-bridge-setup.exe.sig trezor-bridge-setup.exe
Permissions & security model
Bridge intentionally binds to localhost and uses platform services to access USB. It does not open ports to external networks. When a web page requests access to Trezor via Trezor Connect, you should verify the requesting site's URL and only approve connections from trusted domains. Bridge itself should be installed from official sources and kept updated; updates often include security and compatibility fixes.
Using Bridge with web apps
Most web wallets and services that support Trezor will detect Bridge automatically if it is running. On a supported site, initiate the 'connect hardware wallet' flow, choose Trezor, and follow prompts. The device must be connected via USB and unlocked (enter PIN if set) to complete account discovery and signing. Bridge handles low-level transport; your browser interacts with a higher-level API provided by Trezor Connect.
Troubleshooting common issues
- Bridge not detected: ensure the service is running — restart Bridge or your computer. On Windows, check Services or restart the installer. On macOS, ensure you allowed the app in Security & Privacy if Gatekeeper blocked it.
- Device not recognized: try a different data-capable USB cable, a different port (avoid hubs), and ensure no other software (e.g., unused drivers) is interfering.
- Permission / WebUSB errors: some browsers increasingly restrict direct USB access; Bridge avoids this but make sure you approved connection prompts in the web app and allowed device access.
- Legacy issues: older Bridge versions might not support newer devices or OS changes — update to the latest release from the official site.
Maintenance & updates
Keep Bridge updated for stability and security. Many installers include an auto-update mechanism or prompts when a new version is available. If you manage systems centrally (e.g., in an enterprise), obtain Bridge installers from the official download server and distribute through your standard software deployment tools after validating checksums.
Privacy & network considerations
Bridge is local-only; by design it does not transmit your keys or sensitive data to remote servers. However, web apps you use may interact with external APIs (price feeds, explorers). Always review the privacy policy of services you connect to and prefer using trusted sites. For advanced privacy, run local backends or use privacy-focused explorers where available.
For developers
Developers can integrate with Trezor using Trezor Connect, which will automatically route through Bridge if present. When testing, ensure the Bridge API endpoints are reachable on localhost and consult the Trezor Connect docs for API methods, event handling, and best practices when prompting users for device operations.