Trezor Bridge — The Secure Gateway to Your Hardware Wallet

What is a "bridge" and why it matters

A hardware-wallet bridge is a small, trusted application (a background service or desktop app) that lets your browser or desktop dApps talk securely to a hardware wallet connected to your machine. Browsers are sandboxed and often cannot access USB or Bluetooth devices in a consistent way across platforms — the bridge fills that gap by exposing a local API the dApp can call while the bridge handles the device communication.

The critical security property: private keys remain inside the hardware device. The bridge simply relays signing requests and returns signed transactions — it should never request, display, or store your seed.

How the bridge works (high level)

• Local service: The bridge runs on your machine and listens on localhost or via native IPC.
• Browser handshake: A dApp calls the bridge API to request account discovery or signing.
• Transport: The bridge forwards requests to the device over USB (HID), WebHID/WebUSB, or Bluetooth.
• On-device confirmation: The device displays transaction details and requires a physical button press to sign.

Because the device displays transaction fields, you get a tamper-resistant view of the critical signing data — even if your host machine is compromised.

Before you install — safety checklist

• Buy your hardware wallet from an authorized seller to avoid supply-chain risk.
• Type vendor domains directly into your browser; avoid email or social links.
• Have pen & paper or a metal backup ready to secure your recovery seed during initial setup.
• Consider using a dedicated browser profile for web3 interactions to reduce extension and cookie exposure.

Installing and running the bridge — step by step

1. Download from the verified source: Visit the vendor’s official downloads page (type it manually or use a trusted bookmark) and download the bridge or official manager app.
2. Verify the binary: If checksums or PGP signatures are provided, verify the download to confirm integrity.
3. Install the app: Run the installer and grant only the permissions needed (USB/HID access, localhost network).
4. Start the bridge: Confirm the bridge/service is running (system tray / menu bar) before connecting your device.
5. Connect and unlock the device: Use the official cable, unlock with your PIN on-device (never type the PIN into the host), and approve any trust prompts on the screen.
6. Open your dApp and connect: Choose the hardware wallet option; the dApp will request the bridge to open a session. Confirm requested accounts or addresses and approve on-device when required.

On every signing request — always verify recipient, amount, and fees on the device display before confirming. The device screen is the final authority.

Daily workflows — receive, send, and sign

Receiving

1. Generate a receive address in your wallet manager or dApp.
2. Verify the exact address on the hardware device screen before sharing.
3. Use the verified address for incoming funds.

Sending

1. Create the transaction in the dApp.
2. The bridge forwards the signing request; the hardware device shows transaction details.
3. Carefully verify every field on-device; if it doesn't match the app, cancel the operation.
4. Confirm on-device to sign and broadcast the transaction.

Smart contract interactions

Contract calls can be complex. Prefer dApps that decode contract calls into human-readable summaries. If the device shows only partial info, be conservative: avoid granting unlimited allowances and consider splitting approvals.

Security best practices

• Verify downloads: Always check signatures or checksums of bridge binaries when available.
• Confirm on-device: The hardware display is your protection against host manipulation — use it every time.
• Limit browser extensions: Extensions increase attack surface; keep them minimal in your web3 profile.
• Use minimal approvals: For ERC-20 approvals, grant only the necessary allowance and revoke unused allowances periodically.
• Back up offline: Store your recovery seed offline, in multiple secure physical locations; consider a metal backup for durability.
• Keep software updated: Update bridge software and device firmware only via official channels.

Troubleshooting common issues

Bridge not detected

• Check the system tray/menu bar for the bridge process and restart it if needed.
• Restart your browser or try a fresh browser profile without extensions.
• Try a different USB cable/port — some cables are charge-only.

Device not showing expected details

Firmware compatibility or update problems

• Install firmware updates only from the official manager or vendor site.
• If a firmware update fails, follow the vendor’s recovery steps and avoid entering your seed into any tool.

Developer notes — integrate safely

If you build dApps that integrate with a bridge, follow these principles:

• Never request seed phrases or private keys.
• Present clear, human-readable transaction summaries before requesting signatures.
• Validate request origins and display origin information where possible so the user can verify which site initiated the request.
• Support graceful error handling for device lock, disconnects, or firmware mismatches and provide clear remediation paths.
• Prefer standardized transports (WebHID/WebUSB) where feasible and provide fallback mechanisms for browsers that lack support.

Well-documented, minimal APIs and clear UX reduce accidental user errors and improve security.

Advanced workflows

For very high-value or privacy-focused use cases consider advanced options:

• Air-gapped signing: Generate unsigned transactions on an online machine, sign on an offline device, and then broadcast the signed transaction from the online machine.
• Multisignature: Use multisig schemes to split signing authority across multiple devices or people for better resilience.
• Shamir & split backups: Distribute seed shares across custodians using secret-sharing schemes if supported by your workflow.

Frequently asked questions

Will the bridge ever ask for my recovery seed?

No — a legitimate bridge will never request your recovery seed. If any software asks for the seed, it is malicious.

Can I run the bridge on multiple machines?

Yes — install the bridge only on trusted machines. Each machine should verify the binary just like the first.

Is a bridge required?

Not always. Some modern browsers and dApps can access devices through WebHID/WebUSB directly. Bridges improve compatibility across platforms and provide a simpler UX for many users.