Trezor Bridge — The Secure Gateway to Your Hardware Wallet®

A practical, security-first 2500-word guide explaining how Trezor Bridge connects your Trezor device to browser-based wallets and dApps, how to install and configure it, and how to use it safely as the bridge between your web3 apps and the cryptographic hardware that secures your keys.

Overview — what is Trezor Bridge?

Trezor Bridge is a lightweight background service that runs locally on your computer and exposes a secure, local API for browser-based applications to interact with Trezor hardware wallets over USB (and in some setups, over native channels). It enables web wallets and dApps to request operations — such as address retrieval or transaction signing — without directly accessing the USB hardware layer. Bridge's role is strictly as a communication relay that respects origin checks and requires on-device confirmation for all cryptographic operations.

Important: Bridge never has access to your private keys or recovery seed. All signing and secret operations occur on the Trezor device itself; Bridge only forwards requests and responses.

Why Bridge exists and who needs it

Browsers have limited or complex support for direct USB access and varying security models. Bridge provides a stable, consistent interface for web3 integrations while keeping a clear separation between web code and the hardware device. Users who interact with web wallets, decentralized exchanges, or dApps that support Trezor will typically need Bridge installed to use those services in-browser. Developers building web integrations also rely on Bridge to support a smooth connection flow across platforms.

Download Bridge from the official source

  1. Navigate to the official Trezor website: trezor.io/start or the dedicated Bridge download page.
  2. Select the correct installer for your operating system (Windows, macOS, Linux) and download it. Bridge is cross-platform and the installers are tailored to each OS.
  3. When possible, verify the checksum or signature provided on the official site to ensure the file wasn't tampered with during download.
  4. Only download Bridge from the official Trezor domain — do not use search results that point to unknown or third-party domains.

Downloading from the correct domain and verifying installer integrity are essential steps to avoid compromised installers that could undermine the security of your device interactions.

Install and run Bridge

Installation is straightforward. Bridge runs as a background application and listens on a local port (localhost) for requests from your browser. After installing, most systems will start Bridge automatically; otherwise, you can launch it manually from the system tray or application menu.

  1. Run the downloaded installer and follow the platform-specific prompts. Administrator privileges may be required.
  2. After installation, open your browser and visit a Trezor-enabled web wallet or trezor.io/start. The site should detect Bridge automatically.
  3. If the site does not detect Bridge, ensure the Bridge service is running (look for the Bridge icon in system tray/menu bar) and restart the browser.

If you prefer not to use Bridge, many users can use the Trezor Suite desktop application or native integrations that do not require the browser bridge. However, Bridge is the de facto option for most browser-based dApp interactions.

How Bridge communicates with web apps

Bridge exposes a local HTTP or WebSocket API that web pages can call via an official library (such as Trezor Connect). When a site requests access, Bridge forwards the call to the Trezor device; the device then prompts for user confirmation when needed (for example, to approve a transaction). Once the user approves on-device, the signed data is sent back through Bridge to the web page which can then broadcast the transaction to the network.

Key design elements:

  • Localhost-only: Bridge listens only on localhost to prevent remote access.
  • Origin validation: The integration library and Bridge use origin checks to ensure requests come from the expected web page.
  • User confirmation: Any cryptographic operation requires direct confirmation on the Trezor device.

Using Bridge with dApps and web wallets

  1. Open a supported web wallet or dApp and choose the option to connect a Trezor or hardware wallet.
  2. The web app will invoke Bridge through Trezor's connection library and request available addresses or initiate a signing request.
  3. Connect your Trezor device (via USB) and unlock it by entering your PIN on-device.
  4. Open the appropriate app on the device (if required) and confirm the requested operations on-device. Only after confirmation will the device produce signatures or reveal public addresses.

Always verify the destination address and transaction amount on the Trezor device screen before approving any signature.

Security model & best practices

Bridge is built to minimize risk while enabling web interactions. However, secure behavior by users is crucial:

  • Only install Bridge from trezor.io and keep it updated.
  • Verify the domain of any web wallet before connecting — phishing sites may mimic legitimate dApps.
  • Confirm all transaction details on the Trezor device display; the device is the ultimate source of truth for what you sign.
  • Use a dedicated, secure computer for managing large holdings and avoid public or compromised networks when performing sensitive operations like firmware updates or large transfers.
Remember: Bridge does not and cannot access your seed or private keys. If an installer or other software tries to read your seed, it's malicious. Only enter your recovery seed into official device recovery prompts — never into websites or random apps.

Permissions and privacy considerations

Bridge runs locally and should not request personal data. However, when connecting to dApps you may grant them access to view addresses or request signed messages. Be conservative with permissions and avoid granting persistent authorizations to apps you do not trust. Treat address exposure as public information — avoid reusing addresses for privacy when appropriate.

Developer guidance

Developers building Trezor integrations should use the official libraries and follow security best practices. Key recommendations:

  • Use Trezor Connect or equivalent, which abstracts Bridge communication and handles origin checks and UX flows.
  • Only request permissions necessary for your feature and clearly explain why you need them in the UX.
  • Implement robust error handling for Bridge detection, device disconnection, and user cancellation flows.
  • Test across browsers and platforms — Bridge and browser USB behavior can differ in edge cases.

Keep third-party libraries updated and audit any dependencies that interact with Bridge to reduce supply-chain risks.

Troubleshooting common Bridge issues

Bridge not detected by the browser

  • Ensure Bridge is running: look for the Bridge icon in the system tray or menu bar and, if necessary, start the service manually.
  • Restart your browser — some browsers cache device state.
  • Check for firewall or security software that may block localhost ports; configure exceptions if needed.
  • Reinstall Bridge from trezor.io/start if problems persist.

Device not recognized or permission errors

  • Use a known-good data-capable USB cable and connect directly to the computer rather than through hubs.
  • Unlock the device and open the required coin app when the dApp requests it.
  • Confirm prompts on the device — without on-device approval signatures won't be produced.

Origin mismatch or unauthorized requests

If you see origin mismatch errors, double-check the web page domain and make sure you're interacting with a trusted site. If in doubt, cancel and re-open the web app from a bookmarked link or the official site.

Updates and maintenance

Keep Bridge and Trezor device firmware up to date. Updates often patch security vulnerabilities and add compatibility for new features and chains. Best practices:

  1. Install Bridge updates when prompted by the Bridge app or when notified via the official site.
  2. Use Trezor Suite or official update channels to update device firmware. Firmware updates require on-device confirmation.
  3. For developers, monitor release notes for breaking changes and update integrations accordingly.

Never install Bridge or firmware from untrusted sources. If an update process looks suspicious, verify links through the official Trezor domain.

Frequently asked questions

Does Bridge store my private keys or seed?

No. Bridge never has access to private keys or the recovery seed. It only facilitates communication between the browser and device; all signing operations occur on the hardware, under your physical control.

Can I use my Trezor without Bridge?

Yes. You can use Trezor Suite desktop, native integrations, or other supported clients that do not rely on Bridge. Bridge is specifically useful for browser-based dApps that need a local bridge to interact with hardware devices.

Is Bridge open source?

Parts of the Trezor ecosystem are open source. For Bridge, libraries and components may be available on the official Trezor GitHub repositories — review them to understand the implementation and security considerations.

Resources & official links