Trezør Bridge — Connect Your Web3 World Securely (Independent Guide)

Executive summary

A hardware-wallet bridge is a small, trusted application that enables a browser or desktop dApp to communicate with a hardware wallet connected to your computer or mobile device. The bridge relays address discovery and signing requests while preserving the device’s core security property: private keys never leave the hardware. This guide covers the bridge’s role, safe installation and usage, user-facing workflows, developer integration best practices, troubleshooting, and advanced operational security strategies.

Intended audience: everyday users who want to safely use dApps with a hardware wallet, and developers integrating bridge-compatible flows into their applications.

Why bridges exist — problem & solution

Modern browsers are sandboxed for security, but they lack standardized, universally available APIs to talk directly to hardware wallets across all operating systems and browser versions. A bridge solves this compatibility gap by exposing a local API the browser can contact (usually on localhost) and forwarding those messages to the hardware device via USB, WebHID/WebUSB, or Bluetooth.

The bridge’s job is deliberately narrow: translate and forward requests, surface device prompts, and let the device present a tamper-proof view of transaction data for user confirmation. A well-designed bridge must never ask for or store recovery seeds, must be verifiable (code-signed), and must require explicit on-device confirmation for any operation that moves or authorizes funds.

How a bridge works — technical overview

Architecture components

• Local bridge daemon/service: A small background application that listens on localhost (or uses native IPC) and interacts with USB/BLE drivers to reach the hardware wallet.
• Browser/dApp client: The webpage or desktop app that calls the bridge API to request address discovery and signing operations.
• Transport: Communication channels include USB HID, WebHID/WebUSB (when supported), or Bluetooth Low Energy for wireless devices.
• On-device confirmation UI: The hardware wallet displays transaction fields on its screen; the user confirms with physical buttons.

Security controls

• On-device verification: The device presents critical signing details for the user to confirm — this is the ultimate defense against altering transaction data in the host environment.
• Code signing and checksums: Official bridge binaries should be signed and accompanied by checksums or PGP signatures to verify integrity before installation.
• Origin awareness: Bridges should log and, when possible, surface the origin (which dApp requested a signature) so users can spot suspicious requests.
• Least privilege: Bridges should request only the minimal OS permissions required (device access, local loopback) and avoid unnecessary privileges.

Installing a bridge safely — step-by-step

Step 1 — Verify source & download

Type the manufacturer’s domain directly into your browser or use a trusted bookmark. Avoid links from email, social posts, or search results you don’t recognize. Download the bridge or the official manager app from the verified downloads page.

Step 2 — Verify binary integrity

If the vendor provides checksums or PGP signatures, verify them before installing. On macOS/Windows/Linux use the appropriate checksum/PGP verification tools; this helps ensure you didn’t download a tampered binary.

Step 3 — Install and run

Install the bridge per the vendor’s instructions. On first run you may see OS dialogs requesting permission for device or network access. Grant only the permissions necessary for the bridge to access hardware devices and listen on localhost.

Step 4 — Connect your hardware wallet

Connect the device using the official cable (or pair via Bluetooth if supported). Unlock the device by entering your PIN on the device itself — never type your PIN into the browser or OS prompt. The device will show a connection prompt; trust the host only if you initiated the connection.

Step 5 — Connect from a dApp

Open the dApp and select “Connect Wallet” → choose the hardware option or bridge entry. The dApp will request the bridge to open a session and may ask for account/address discovery. Approve the connection as prompted in the bridge UI and on your device.

Day-to-day user workflows

Receiving assets

1. Create or navigate to the account in your wallet manager or dApp.
2. Generate a receiving address and verify the address on your hardware device’s screen matches what the app shows.
3. Share the address with the sender or use it for deposits.

Sending assets

1. Create the transaction in your dApp or manager app.
2. The bridge forwards the request to the device; the device shows the recipient address, amount, and fees.
3. Carefully verify each field on-device. If anything looks wrong, cancel the operation.
4. Confirm on-device to sign; the bridge returns the signed transaction to the app for broadcast.

Approving smart contract interactions

When interacting with smart contracts (approvals, swaps, DeFi positions), the device may only show a decoded summary or limited info. For complex contracts, prefer dApps that provide decoded, human-readable summaries and consider using permit-style minimal approvals rather than max approvals. If in doubt, cancel and inspect on a trusted block-explorer or use a safer contract UI.

Security best practices (must-read)

• Never reveal your recovery phrase: A legitimate bridge, dApp, or support team will never ask for your seed. Treat the seed like the keys to a safe deposit box.
• Confirm on-device, always: The device screen is the final truth — verify address, amount, and any contract data shown there before approving.
• Use a dedicated web3 browser profile: Keep your dApp browsing separate from daily browsing to reduce cross-site contamination from malicious extensions.
• Keep software up to date: Bridge, firmware, and dApp updates can include critical security patches; install updates from official sources only.
• Minimize approvals: For ERC-20/ERC-721 approvals, grant the smallest allowance necessary and periodically revoke unused approvals through a reputable interface.
• Use passphrases only if you understand them: A BIP39 passphrase creates a hidden wallet but is unrecoverable if forgotten. Use it only with clear plans for secure storage and recovery.

Developer guidance — integrate safely

If you’re a developer building dApps that integrate with a bridge, follow these core principles:

• Never request seeds or private keys. Only request address discovery and signing operations.
• Show clear intent: Present a readable transaction summary to the user before calling the bridge for a signature.
• Validate origin: Where possible, include origin checks and present origin or domain information to the user or device so they can recognize the requester.
• Graceful error handling: Handle states such as device locked, device disconnected, bridge not running, or firmware mismatches with clear user guidance and recovery steps.
• Prefer standards: Where possible support WebHID/WebUSB and follow existing wallet interoperability specs to reduce the need for bespoke binaries.
• Limit scopes: Request as little as possible from the user; e.g., request the account addresses you need rather than all accounts if feasible.

Document full request/response schemas, error codes, and user flows so integrators can implement predictable, secure interactions.

Troubleshooting — common problems & fixes

Bridge not running / browser cannot detect it

• Check the system tray/menu bar for the bridge process. Restart it if necessary.
• Restart the browser or try a fresh browser profile.
• Temporarily disable privacy extensions to check if they block localhost requests.

Device not detected

• Use a different USB port or data-capable cable (some cables only charge).
• Ensure the device is unlocked with the PIN and on the home screen.
• Update OS USB drivers if required (Windows may need drivers for older kernels).

Transaction details differ on-device

Firmware & compatibility warnings

• Only install firmware updates from the official vendor. If a bridge warns the firmware is incompatible, consult the vendor’s support pages.
• Do not enter your recovery seed to "fix" firmware or connection problems.

Advanced topics

Air-gapped signing workflows

For maximum safety, some users adopt air-gapped workflows: transactions are created on an online machine, exported as unsigned payloads (file or QR), moved to an offline machine with the hardware wallet for signing, and the signed payload is returned for broadcast. Bridges are not involved in fully air-gapped flows but understanding them is useful for high-value operations.

Multi-signature & enterprise use

Bridges can be part of multisig setups where multiple hardware wallets sign off on high-value transactions. Enterprises should combine bridges with formal access controls, audited signing orchestration, and documented recovery procedures.

Open source & audits

Prefer bridges and manager apps that are open source and have undergone third-party security audits. Audits don’t eliminate risk but increase transparency. Combine audits with vigilant operational security.

FAQ

Will a bridge ever ask for my recovery phrase?

No. No legitimate bridge or vendor support will ask you to type your recovery phrase. If you are asked to provide it anywhere, stop immediately and assume you are being targeted by a scam.

Can I run the bridge on multiple machines?

Yes. You can install the bridge on any machine you control, but each machine must run the bridge and the device must be connected and unlocked to sign transactions.

Is a bridge required?

Not always. Some browsers support WebHID/WebUSB which allow direct device access for some workflows. Bridges remain useful for broader compatibility across browsers, OS versions, and dApps.

What if the bridge project is abandoned?

If an official bridge is deprecated, the vendor should provide migration guidance. Avoid third-party forks unless you can verify their integrity and security through signatures and audits.

Quick security checklist before signing

1. Downloaded the bridge from an official, verified source and verified checksums/signatures.
2. Confirmed the hardware device is genuine and untampered.
3. Unlocked the device and ensured the dApp origin is expected.
4. Verified recipient address, amount, and fees on the device screen.
5. Only after on-device verification, pressed the confirmation button(s).