Overview
Trezor Bridge is the communication layer that enables modern web browsers and native applications to talk with Trezor hardware wallets (like Model T and One). It ensures messages and transactions sent to the device are routed securely, reliably, and with user consent. Rather than exposing raw USB or HID details to every webpage, Bridge acts as a controlled gateway — minimizing attack surface while preserving user control.
Why Trezor Bridge matters
Hardware wallets are built to isolate private keys from networked environments. But to provide a smooth user experience (like signing a transaction in a web wallet), a secure, trusted mechanism to pass requests from the browser to the device is required. Trezor Bridge delivers:
- Compatibility — Works across major browsers and operating systems.
- Security — Minimizes direct exposure of device APIs to untrusted web pages.
- Usability — Seamless connection flows and clear prompts on the device for user approvals.
How it works (high-level)
Trezor Bridge runs as a small, local background service on the user’s machine. When a web page or native app wants to interact with a Trezor device, it sends a request to Bridge. Bridge authenticates and forwards the request using the USB/HID stack to the device. The Trezor device shows a clear confirmation UI (device screen + buttons or touchscreen) so the user approves or rejects every sensitive action.
Security features & best practices
Device-first confirmations
All critical actions (e.g., transaction signing, revealing public keys) must be approved on the physical device. This design prevents rogue web pages or malware from stealing private keys; approval always requires local, physical confirmation.
Minimal privilege exposure
Bridge scopes actions — it doesn’t grant arbitrary access to private key material. Instead, it forwards structured requests and relays responses. Web applications receive only what the device authorizes.
Keep Bridge up-to-date
Bridge receives security updates and compatibility patches. Installing official Bridge releases and firmware updates for your Trezor device reduces risk and ensures compatibility with the latest wallets and browsers.
Common user flows
1. First-time setup
Install Trezor Bridge, connect your device, open the official Trezor web app or Trezor Suite, and follow on-screen steps to initialize the device. Bridge will detect the device and manage USB permissions automatically.
2. Signing a transaction
When sending funds from a web wallet, the transaction is passed to Bridge, which forwards it to the device. The device shows the transaction details (amount, recipient, fee) on its screen. After you confirm, the device signs and returns the signature through Bridge to the wallet for broadcast.
3. Firmware updates
Bridge can be used to deliver firmware updates. Always verify update prompts and only use official firmware from Trezor to avoid supply-chain risks.
Troubleshooting & tips
- Browser can't connect: Make sure Bridge is installed and running; restart the browser or Bridge if needed.
- Device not detected: Try a different USB cable or port; some cables are power-only and won’t transfer data.
- Permissions on macOS or Linux: Confirm OS-level USB permissions and allow Bridge to run when prompted.
- Keep firewall/AV rules permissive for Bridge: Rarely, strict security software can block Bridge’s local service port.
Privacy considerations
Trezor Bridge does not collect private keys or wallet seeds. Its role is purely a local transport layer. Still, users should be mindful of which websites they connect to — only connect to trusted wallet providers and verify URLs carefully.
Integration for developers (brief)
Developers building wallet integrations talk to Bridge using the standardized API provided by Trezor (and official client libraries). The API allows apps to request device lists, send APDU-like commands, and handle responses. Always follow the official developer guides to avoid introducing security issues.
Future-proofing & alternatives
While Bridge is widely used, the ecosystem evolves. Native browser protocols, WebUSB, and platform-integrated solutions can complement Bridge in some environments. However, the device-first confirmation model remains fundamental — even new transports must preserve user approvals on the hardware itself.