Overview & Key Benefits
Modern browsers intentionally limit low-level USB access to reduce attack surface. Trezor Bridge fills a necessary role: it exposes a controlled local API so authorized web apps and desktop clients can request operations from an attached Trezor device. Crucially, the device itself remains the authority for private key operations — Bridge simply relays messages and enforces that final user approval must occur on-device.
Bridge runs on the user's machine and is not a cloud relay. The communication path stays local between your browser or app and the attached hardware wallet.
Every sensitive action — revealing keys, exporting data, or signing transactions — requires explicit confirmation on the device display and buttons.
Bridge is designed for mainstream desktop operating systems so users get a consistent experience whether they run Windows, macOS, or popular Linux distributions.
The local API simplifies discovery and messaging for integrators. Implement error handling for user cancellations, disconnects, and timeouts to create robust integrations.
How It Works — plain language
The flow is intentionally simple and secure: a website or application asks Bridge to perform an operation (for example, request an address or sign a transaction). Bridge forwards the structured request to the Trezor device over USB. The device displays the exact details and waits for your physical confirmation. After you confirm, the device performs the operation and returns the result via Bridge to the calling app. Private keys never leave the physical device.
- App requests device access through Bridge’s local API.
- Bridge enumerates connected devices and forwards the request.
- Device displays the operation details and prompts for confirmation.
- User confirms on the device and the operation completes; Bridge relays the result back.
Installation — step-by-step guidance
These instructions outline typical install flows. Behavior may vary between OS versions and desktop environments; follow platform prompts and grant permissions only when you understand the intent.
- Run the local installer and authorize administrative privileges if prompted. These elevated permissions are typically required to register device helpers or drivers.
- After install, restart your browser so it recognizes the Bridge service.
- Plug in your Trezor with a data-capable USB cable. When an application requests access, examine the request details and verify on-device before approving.
- Open the installer package and accept any system prompts for USB access or system extensions if shown. macOS may request user approval for hardware access.
- Restart your browser once install completes and then connect your Trezor device for use.
- Install the distribution-appropriate package (deb, rpm, or binary). If necessary, add udev rules so non-root accounts can access connected hardware wallets.
- Start Bridge under your user account and restart the browser. If the device is still not detected, verify udev rules and file permissions.
Security best practices
Bridge is intentionally narrow in scope, but your environment still matters. Use these practical security measures to keep your crypto operations safe:
- Verify installer checksums or signatures whenever provided to ensure integrity.
- Use a dedicated browser profile for crypto activity to reduce exposure from extensions and cookies.
- Never type or paste your seed phrase into any website or app — seed phrases belong only on the hardware device.
- Always validate addresses and amounts on the device display and not just on the host screen.
- Keep device firmware and Bridge updated, but verify release notes and integrity before applying updates.
Troubleshooting — common issues & fixes
Most problems are related to cables, permissions, or conflicting software. Try these steps in order to isolate and fix common problems quickly.
- Device not detected: swap USB ports and cables (use a data cable). Restart the browser and try reconnecting.
- Permission prompts missing: some OSes show a one-time permission dialog; replug the device to trigger it and accept prompts carefully.
- Conflicting USB tools: temporarily disable USB-monitoring or virtualization tools that might intercept device traffic during troubleshooting.
- Failed operations: confirm the device displays the expected details. Cancel and retry if anything looks unfamiliar.
Notes for developers & integrators
If you build integrations, prioritize clarity in the user experience. Make it obvious when an operation requires on-device confirmation, present clear transaction details, and handle error cases gracefully.
- Show the user an exact preview of the transaction or data they will approve on-device.
- Implement exponential backoff for retrying device calls and provide clear error messages.
- Log locally for diagnostics but never capture seed or private key material in logs. If users share logs for support, provide guidance for redaction.
Frequently Asked Questions
Do I always need Bridge to use my Trezor?
Many browser-based wallets and decentralized applications rely on a local Bridge to communicate with hardware wallets. Native desktop suites may use other connection methods and sometimes do not require a separate Bridge. Check the client you plan to use for exact requirements.
Can Bridge access my private keys or seed?
No — private keys and seed phrases remain on the hardware device. Bridge relays structured requests and responses but does not have privileges to export private keys or seed data.
Is running Bridge on a server a good idea?
Running Bridge on a headless server is not recommended for typical users. Hardware wallets are designed to be used interactively so users can physically verify and confirm sensitive operations. If you have a specialized use case, design the environment with strict physical and network controls.
If you need more help, collect useful diagnostics when reporting issues: OS version, browser version, Bridge version (if visible in installer), Trezor model and firmware, and a concise reproduction of the problem. When sharing logs, remove any sensitive material.