Trezor Bridge

What is Trezor Bridge?

Trezor Bridge is the official background service developed by SatoshiLabs that enables communication between your Trezor hardware wallet and web browsers or Web3‑enabled applications. It acts as a secure intermediary (or “connector”) that relays requests from your browser to the hardware device over USB, and sends responses back, ensuring sensitive operations never expose private keys or seed phrases.

It replaces older browser plugin/extension methods (e.g. the Chrome Connector) with a more robust, cross‑platform solution compatible with Windows, macOS, and Linux. :contentReference[oaicite:0]{index=0}

Why Trezor Bridge Is Necessary

• Browser Security Restrictions: Modern web browsers restrict direct USB access for security, preventing unauthorized hardware interactions. Bridge overcomes this by running locally and serving as the trusted middleman. :contentReference[oaicite:1]{index=1}
• Cross‑Platform Compatibility: Works on Windows, macOS, Linux. Ensures consistent behavior across OS USB stack differences. :contentReference[oaicite:2]{index=2}
• Improved Reliability: No dependency on installing browser extensions, which are often deprecated or broken; Bridge tends to be more stable and always updated. :contentReference[oaicite:3]{index=3}
• Enhanced Security: All sensitive operations (signing, firmware updates etc.) happen on the Trezor device. Bridge only passes valid requests and responses. :contentReference[oaicite:4]{index=4}
• Seamless Integration with Web3 & dApps: Enables usage of browser‑based wallets, decentralized applications, and services that need hardware wallet authentication. Without Bridge, many such services cannot detect the device reliably. :contentReference[oaicite:5]{index=5}

How Trezor Bridge Works

Architecture & Data Flow

When you connect your Trezor via USB, here’s a simplified flow of how requests are handled:

1. Your browser (or Web3 app) attempts to interact with the hardware wallet (e.g. get public address, sign transaction).
2. Because browsers cannot directly talk to USB devices for many operations, a request is sent to Trezor Bridge running locally – typically via a loopback/localhost HTTP API. :contentReference[oaicite:6]{index=6}
3. Bridge identifies the connected Trezor device through the OS USB layer. This involves the USB transport, driver/hardware detection. :contentReference[oaicite:7]{index=7}
4. Bridge forwards the request (e.g. transaction details) to the hardware wallet. The device shows the details on its own screen for user verification. :contentReference[oaicite:8]{index=8}
5. User confirms or declines the action directly on the physical Trezor device.
6. If approved, the hardware wallet signs the transaction internally, returning the signed data back through Bridge → browser/app. If declined, nothing is executed. :contentReference[oaicite:9]{index=9}

Supported Browsers & OS

Trezor Bridge supports major desktop operating systems (Windows, macOS, Linux) and works with popular browsers including Chrome, Firefox, Edge, Brave. :contentReference[oaicite:10]{index=10} Note: Some environments may allow WebUSB/WebHID so that Bridge may be optional; however, compatibility and user experience may vary. :contentReference[oaicite:11]{index=11}

How to Install & Setup

1. Download Bridge: Go to the official Trezor site (trezor.io or official portal) and download the version appropriate for your operating system. Always verify the URL/domain is legitimate. :contentReference[oaicite:12]{index=12}
2. Run Installer: / On Windows: execute the `.exe` / `.msi` installer.
   / On macOS: open the downloaded package, move to Applications, grant permissions as required.
   / On Linux: use the appropriate package (`.deb`, `.rpm`, or other) or instructions from Trezor docs. :contentReference[oaicite:13]{index=13}
3. Allow Permissions: Depending on your OS, you may need to allow Bridge access to USB devices, allow network / localhost communications, allow device drivers. Follow system prompts. :contentReference[oaicite:14]{index=14}
4. Restart Browser/App: After installing, restart your browser or reload the Web3‑browser based wallet so it picks up the Bridge service. Some systems may require a reboot. :contentReference[oaicite:15]{index=15}
5. Connect Physical Device: Plug in your Trezor via USB (or USB‑OTG where supported), unlock via PIN/passphrase as needed. :contentReference[oaicite:16]{index=16}
6. Confirm on Device: After actions like signing or firmware update request, carefully verify details on the device screen and accept or reject. Never accept blindly. :contentReference[oaicite:17]{index=17}
7. Update Bridge Regularly: Keep Bridge software up to date via official sources to benefit from security fixes and new improvements. :contentReference[oaicite:18]{index=18}

Security Considerations

• Private Keys Never Leave the Device: All signing and sensitive operations are performed inside the Trezor hardware. Bridge simply transfers data, but private or secret data remains on device. :contentReference[oaicite:19]{index=19}
• Origin & Request Verification: Bridge ensures that requests come from trusted applications or domains. Browser/web apps are not allowed to bypass checks. :contentReference[oaicite:20]{index=20}
• Encrypted Local Communication: Communication between browser and Bridge is local and structured to avoid exposing through network. No third‑party server intermediaries. :contentReference[oaicite:21]{index=21}
• Signed Updates: Bridge installers and updates are cryptographically signed by Trezor / SatoshiLabs; verifying these ensures authenticity. :contentReference[oaicite:22]{index=22}
• Avoid Untrusted Environments: Do not use Bridge in unknown or compromised machines, public computers, or where OS integrity is not assured. Malware can’t directly steal keys, but can trick you into approving bad transactions if you don’t inspect carefully. :contentReference[oaicite:23]{index=23}

Frequently Asked Questions

Do I always need Trezor Bridge?

If you are using Trezor Suite **desktop app**, you may not need Bridge: the desktop “Suite” often handles hardware‑communication natively. Bridge is essential when using browser‑based wallet interfaces or third‑party dApps that require USB detection. :contentReference[oaicite:24]{index=24}

What browsers are compatible?

Major supported browsers include Google Chrome, Mozilla Firefox, Microsoft Edge, and Brave. Some browsers are moving to support WebUSB/WebHID which can reduce reliance on Bridge, but support is not uniform across all OSes. :contentReference[oaicite:25]{index=25}

Is Bridge safe?

Yes, when downloaded from official sources. Bridge doesn’t store private keys. All sensitive tasks are handled by the hardware wallet itself. Security is maintained through device confirmation, update signing, and controlling origin of requests. :contentReference[oaicite:26]{index=26}

What if the device is not detected?

Common fixes include checking USB cable/port, ensuring Bridge service is running, allowing USB permissions on the OS, restarting the browser, disabling conflicting browser extensions, and making sure the installed Bridge version is up to date. :contentReference[oaicite:27]{index=27}

Will Bridge be needed forever?

Probably not in all situations. As browser APIs evolve (WebUSB, WebHID, etc.), more browsers may connect directly to Trezor hardware without Bridge. But until then, Bridge remains the most reliable and secure method for many users. :contentReference[oaicite:28]{index=28}