In the evolving landscape of cryptocurrency and decentralized applications, bridging the gap between desktop browsers and hardware wallets is essential. Trezor Bridge functions as this secure intermediary, enabling communication between web-based wallet interfaces and your Trezor Hardware Wallet. Whether you're logging into dApps, managing accounts via Trezor Suite, or initiating transactions via Trezor Login flows, Bridge facilitates this communication in a safe and permissioned manner.
Trezor Bridge is a small native service (daemon) installed on your operating system (Windows, macOS, Linux) that listens on a localhost port and relays commands from browser or external applications to your connected Trezor device. It ensures communication is encrypted, that only approved commands are passed to the device, and that no private key material ever leaves the hardware. The Bridge does not require cloud servers; it works locally by default.
Modern browsers generally cannot access USB or HID devices directly for security reasons. The Bridge serves as a local “proxy” to allow web applications to “speak” to your Trezor device using a well-defined API. Without Bridge (or an equivalent mechanism), web wallets would not be able to detect Trezor, request approval, or sign transactions.
- Using Trezor Login to authenticate into web services - Executing coin transactions via Trezor Suite - Connecting your device to decentralized applications - Interacting with smart contracts and dApps requiring signature - Recovering accounts or exporting public keys
Users should always download Bridge from official sources (such as Trezor.io/start) or the official repository, verify the cryptographic signature, and ensure their device firmware is up to date. Never install Bridge from untrusted mirrors.
Once Bridge is installed and running, it listens on a localhost interface (e.g. 127.0.0.1) and responds only to authorized applications connecting via approved endpoints.
The communication chain can be simplified as:
The native application runs as a background service, using minimal resources. It handles USB / HID device access, message queuing, and keeps track of sessions and permissions. It also implements a basic access control list to let only known origins talk to it.
Web applications (wallets, explorers, dApps) include a JavaScript client library that knows how to talk with Bridge, ask for device enumeration, and request operations. Typically this library is integrated into Trezor Suite or any front-end that supports Trezor devices.
The Trezor device runs embedded firmware that listens for APDU-like commands (application protocol data units). Requests such as “get public key”, “sign message”, or “decrypt data” are processed securely inside the device. The user must approve on-device, ensuring no external application can force actions silently.
- **Ephemeral sessions**: When a web app opens a session, Bridge prompts the user only once per session (or per operation). - **Origin whitelisting**: Bridge remembers approved origins (domains) and only opens pipes for recognized sites. - **Timeouts and revocation**: Inactivity or manual revocation invalidates sessions and demands re-approval. - **Least privilege**: Each request is scoped — e.g. signing only a transaction, not full device control.
Bridge never sees or handles your private key. It merely passes along encrypted commands. Signing, decryption, and sensitive operations happen entirely inside the Trezor device. This design ensures that even if your computer is compromised, your keys stay secure.
- Requests from the browser to Bridge include origin metadata; Bridge verifies the origin matches the certificate or expected domain - Message payloads are checksumed and validated - The device itself may verify that the command came via Bridge and not a malicious channel - Bridge updates are signed and verified locally before installation
Bridge binds to localhost by default; binding to external interfaces is disabled. This minimizes exposure to remote threat actors.
If your host (computer) is compromised (malware, root access), attackers may attempt to intercept traffic or simulate Bridge endpoints. However, because all operations must be approved on-device (e.g. you must physically press "approve" on Trezor), such attacks are mitigated.
The Trezor device includes secure boot, firmware signing, and user verification. If firmware is corrupted or malicious, the device refuses to operate or forces a recovery workflow.
- You must trust the original Trezor firmware and signature checks
- You must ensure Bridge is downloaded from Trezor.io/start or official sources
- Physical access to device: if someone else can physically press buttons, they can approve malicious operations
- Social engineering: always double-check transaction details before signing
- Bridge does not protect against host-level keyloggers or screen-capture of your interactions in the browser
To begin, visit Trezor.io/start. That page provides the correct Bridge installer for your OS. Always verify the cryptographic signature after download. Once installed, Bridge runs automatically (or via manual start) and awaits browser connections.
Many web services integrate Trezor Login so you can authenticate using your Trezor device instead of a password. The flow is:
This means you never expose passwords or API tokens — it's a cryptographically secure login.
Trezor Suite is the official desktop and web wallet interface provided by Trezor. Suite uses Bridge under the hood to detect your device, fetch account balances, compose transactions, and sign them. When using Suite, Bridge is invisible to you — Suite handles installation, updates, and invocation automatically.
Many third-party wallets or decentralized apps (dApps) support Trezor by integrating with the Bridge API. These apps can:
For security, each of these operations must be explicitly approved on-device, minimizing the risk of rogue web code.
For script-based workflows or power users, you can interact with Bridge via command-line tools or SDKs. Example use cases:
Always design automation so that any signing must pause and require physical device confirmation — never bypass user approval.
Common error conditions to handle:
The client should surface clear user-facing messages (e.g. “Please connect your Trezor and approve”) and allow retry or fallback gracefully.
- Always show detailed transaction summaries before requesting signature - Use canonical JSON serialization or deterministic formats to avoid ambiguity - Avoid large or batch operations in one go — break them to reduce risk - Educate users to verify addresses and amounts on device display - Periodically clear (or expire) approved origin entries to maintain strong security hygiene
If you uninstall Bridge, your browser or applications will no longer be able to communicate with your Trezor Hardware Wallet. You will need to reinstall Bridge (from Trezor.io/start) to restore connectivity. Your wallet accounts and device data are unaffected, as they reside on your Trezor device or in local storage.
Yes — there are installers for Windows, macOS, and Linux. You can install Bridge on multiple machines. Each instance operates independently. Just ensure you always download from official sources and update versions as needed.
Yes. The source code for Bridge is publicly available for audit. You are encouraged to inspect the code or use builds signed by the Trezor team to verify integrity. This transparency helps trust the system.
Trezor Login uses cryptographic challenge-response via your hardware device instead of typing a password. You sign a unique challenge on-device and send the response to the service. This method is more secure because no password or secret is stored or transmitted.
Yes. Bridge supports concurrent connections from multiple clients (e.g. Trezor Suite, a web wallet, CLI tool). It handles multiplexing requests, enforcing permission checks, origin separation, and ensures that only allowed operations pass through. You might see multiple sessions active, but device approval is still required per operation.