Introduction
Trezor Bridge is a purpose-built local application that provides a safe, consistent connection between Trezor hardware wallets and wallet interfaces — both desktop clients and web applications. It exists to bridge the gap between the secure, offline world of a hardware wallet and the modern web, where browsers impose restrictions for safety. Bridge enables developers and users to rely on a predictable transport channel while guaranteeing that cryptographic secrets remain inside the hardware device.
Why a separate Bridge?
Browsers and operating systems intentionally restrict direct hardware access to protect users. This architectural safety produces a fragmentation problem: different browsers support different APIs (WebUSB, WebHID, etc.), and operating systems have different device stacks. Trezor Bridge solves this by providing a single, maintained local service that wallet front-ends can talk to. Bridge handles the low-level device interaction, translating high-level requests from the UI into device protocol calls and returning results. This approach yields a consistent user experience across platforms and reduces the maintenance and compatibility burden for wallet developers.
How Bridge works — a high-level overview
When installed, Bridge runs as a background service on the user’s machine. Wallet apps (web or native) communicate with Bridge through a local channel. Bridge discovers connected Trezor devices, queues requests, and forwards protocol messages over USB/HID to the device. Crucially, the device itself performs key generation, key storage, and signing operations inside its secure element. Any action that reveals sensitive details or signs a transaction prompts the device to display details and request physical confirmation from the user — this ensures that no remote process can silently sign or exfiltrate secrets.
Security model & guarantees
The core security guarantees of the Bridge + device architecture are straightforward:
- Private keys never leave the device: The Trezor hardware retains sole custody of private keys and recovery seeds; Bridge only relays messages.
- On-device confirmation: Signing operations and critical exposes (like revealing an address) require manual confirmation on the device hardware.
- Local transport: Bridge communicates locally; it does not broadcast secrets across the network. Telemetry, if enabled, is limited to non-sensitive diagnostics.
- Signed installers & integrity: Bridge distributions are signed to reduce tampering risk; users are encouraged to verify checksums when available.
Together, these guarantees create a strong security boundary: even if the host computer is compromised, an attacker cannot extract keys or approve high-value transactions without physical access to the Trezor device.
Installation & setup (practical)
Installing Bridge is quick and low-friction. Below are practical steps for major platforms and tips to avoid common pitfalls:
Windows
- Download the Bridge installer for Windows and run the executable.
- Allow the installer to make system changes when prompted — this registers the local service and any driver components.
- After installation, the Bridge service typically starts automatically. If not, launch it from the Start menu.
- Open your wallet interface and connect your Trezor; the wallet should detect Bridge and the device.
macOS
- Open the downloaded .dmg and drag Bridge into Applications.
- On first launch, approve the app under System Preferences > Security & Privacy if macOS blocks it.
- Bridge runs in the background and responds to wallet connection attempts.
Linux
- Install the package suitable for your distribution (deb, rpm) or extract the tarball.
- Enable and start the Bridge service using your distribution’s service manager.
- If needed, add the provided udev rules to allow non-root USB access.
Tip: After installing Bridge, restart your browser if you plan to use a web wallet — this ensures the front-end can detect the Bridge service cleanly.
Developer guidance — integrate with confidence
Developers building integrations with Bridge should follow secure integration patterns:
- Use clear user prompts and do not request operations the user did not initiate.
- Validate device responses and surface meaningful error messages; do not assume success.
- Protect against origin confusion: ensure web UIs use HTTPS and verify origins before prompting users to connect.
- Log diagnostics locally and avoid transmitting potentially sensitive data to remote servers; collect only non-secret metadata when diagnosing issues.
Troubleshooting — common issues and fixes
Most Bridge problems relate to connectivity. The checklist below resolves the majority of issues:
- Try a different USB cable and plug directly into the computer (avoid hubs).
- Ensure the device is unlocked (enter PIN) before attempting to connect.
- Restart Bridge and the browser or wallet app if the device is not detected.
- On macOS, allow the Bridge app in Security & Privacy if prompted.
- On Linux, confirm udev rules are installed so non-root processes can access the device.
If problems persist, collect Bridge logs and provide them to official support while ensuring no sensitive material (like your recovery seed) is shared.
Bridge logs & diagnostics
Bridge produces local logs that help engineers reproduce issues. Developers and support teams typically ask for the Bridge version, operating system, and a concise set of reproduction steps. Before sharing logs, ensure they do not contain anything sensitive — Bridge should not log private keys or seed material, but it’s good hygiene to check logs privately.
Comparing Bridge with native browser APIs
Direct browser APIs (WebUSB, WebHID) are evolving and can allow web pages to talk to devices without a helper application. Bridge remains valuable because it guarantees consistent behavior across browsers and OS versions. For teams supporting a wide user base, Bridge reduces fragmentation and the need for browser-specific workarounds. Over time native APIs may make helper apps less necessary, but currently Bridge provides the most reliable cross-platform experience.
Operational best practices for users
To get the most secure and reliable experience with Bridge, follow these operational tips:
- Download Bridge only from official, verified sources and check installer integrity when possible.
- Keep Bridge and your device firmware up to date; read release notes before updating for any compatibility notes.
- Use a dedicated or well-maintained machine for high-value transactions.
- Always verify the full transaction details on the device screen before approving.
- Keep your recovery seed offline and in secure physical storage (multiple copies in separate locations are recommended).
Privacy & telemetry
Bridge operates locally and minimizes telemetry. When enabled, telemetry is limited to non-sensitive diagnostic information (version numbers, error codes) to help maintainers understand deployment issues. Users who prefer maximum privacy should review Bridge settings to limit or disable telemetry where the option exists.
Advanced topics: headless, CI and automation
Some advanced users or organizations may want to use Bridge in headless environments or integrate with automated tooling. This is possible but must be approached cautiously: automated signing introduces significant operational risk if approvals can be made without direct human oversight. For automated flows, implement strict access controls, logging, and approval gates — and prefer interactive confirmations for any transaction that moves funds.
Frequently asked questions
Q: Can Bridge access my private keys?
A: No. Bridge cannot access or export private keys or recovery seeds. All secret material remains inside the Trezor device.
Q: Do I need Bridge on every machine?
A: Install Bridge on any machine you trust and plan to use with your Trezor device. The device’s security is independent of Bridge; the security boundary remains the hardware wallet and your recovery seed.
Q: What if I see unknown prompts on my device?
A: Disconnect the device immediately and investigate. Unexpected prompts can indicate a misbehaving page or background process. Never approve a prompt you did not initiate.
Wrapping up
Trezor Bridge is a pragmatic, security-first connector that makes modern wallet experiences possible without weakening the core guarantees of hardware wallets. It reduces developer friction, improves cross-platform compatibility, and preserves the critical security properties users rely on: secrets remain on-device, and users must confirm sensitive actions physically. By following the installation steps, troubleshooting tips, and best practices in this guide, users and integrators can enjoy a reliable and secure workflow for managing cryptocurrencies with a Trezor device.