Trezor Bridge — The Secure Gateway to Your Hardware Wallet®

Overview of Trezor Bridge

Trezor Bridge is the software bridge that enables secure communication between your browser or operating system and your Trezor Hardware Wallet. It is a background service (local server) installed on your computer that listens for connections from a browser and relays messages to your Trezor device over USB. This architecture ensures that web apps such as Trezor Suite or web wallets can talk safely to your hardware wallet without exposing sensitive data over the internet.

Why you need Trezor Bridge

Without the Bridge, your browser often cannot access USB devices reliably due to security sandboxing. The Bridge solves this by running locally, handling raw communication with the hardware. Users can then interact via normal web interfaces like Trezor Login portals or Trezor Io Start flows seamlessly. Most importantly, your private keys remain always stored in the device, never in Bridge or your browser.

How It Works

Architecture & communication flow

The communication flow follows these steps:

• Install Trezor Bridge on your computer (Windows, macOS, Linux).
• The Bridge runs a small HTTP/HTTPS server locally, typically at http://localhost:21325 (or similar) and listens to API requests.
• Your browser web app (for example, Trezor Suite or wallet web interface) sends JSON messages to Bridge.
• Bridge forwards commands to the Trezor Hardware Wallet over USB (e.g. signing transactions, retrieving addresses).
• The device responds and Bridge relays the reply back to the browser app.

Supported platforms

Bridge works on Windows (7+), macOS, and many Linux distributions. Whenever you update your OS or browser, make sure your Bridge version is up to date to maintain compatibility.

Version compatibility

Always check the version of Bridge before attempting device communication. Trezor.io maintains version downloads and release notes at their official site.

Setup Guide: Installing & Launching

Step 1: Download from Trezor.io/start

Navigate to Trezor.io/start, where you’ll find instructions tailored for your operating system. Download the appropriate installer and run it. After installation, Bridge starts automatically in many cases.

Step 2: Confirm Trezor Login or Trezor Suite connectivity

After installation, open Trezor Suite or a supported browser interface. When prompted, the system will detect Bridge and ask you to allow access. You may see a prompt “Bridge installed, connect your Trezor device.”

Step 3: Use Trezor Io Start flow (if applicable)

Some users begin via the zero‑config “Trezor Io Start” web flow. This automatically prompts Bridge installation if needed and initiates Trezor Login flow. Through that, the web page can trigger communication via Bridge seamlessly.

Security Features & Best Practices

End‑to‑end isolation

Trezor Bridge only forwards messages; it does not decrypt, store, or manipulate your private keys or sensitive payloads. All cryptographic operations occur on the Trezor Hardware Wallet itself, which isolates private key usage from your OS and browser.

Localhost only

By default, Bridge listens only on your local machine (e.g. localhost), and is not accessible from external networks. This minimizes exposure and attack surface. Only code running on your machine can access it.

Updates & signatures

Always update Bridge when new versions are released; updates often close security bugs or improve device compatibility. Releases are cryptographically signed by Trezor, ensuring you get authentic software.

User prompts and confirmations

Whenever a web app requests action (e.g. signing transaction), your Trezor device must confirm via its screen / buttons. This means even if Bridge is compromised, it cannot perform operations without your physical approval.