ledger.com/start — Browser to Device Connector

Presentation • Overview • Getting started • Security • Implementation guide

Browser to Device Connector

The Browser → Device Connector simplifies secure communication between a user's browser and their Ledger hardware device. This presentation walks through design goals, architecture, UX flow, security considerations, development snippets, troubleshooting and recommended deployment patterns.

Quick facts

Purpose: Pair a browser session with a physical Ledger device securely.
Transport: WebUSB / WebHID / Bluetooth LE (optional).
UX: Minimal steps, clear user consent, robust error handling.

Version: 1.0 — Draft • Audience: Engineers, Product Managers, Security

Overview

The Browser to Device Connector is an integration layer between web applications and Ledger hardware wallets. It handles:

  • Device discovery and transport selection (WebUSB, WebHID, Bluetooth).
  • Secure session establishment and key management patterns.
  • Flow controls for user approval actions like signing and transaction confirmation.
  • Resilient error reporting and user guidance for troubleshooting.

Design goals

  1. Security-first: never expose sensitive material to the web page runtime without user confirmation.
  2. Clear UX: minimize friction and ambiguity for users when connecting devices.
  3. Modular: transport-agnostic core with pluggable adapters.
  4. Observability: good logs for support without leaking secrets.

How it works

High-level flow:

  1. Web app initiates device discovery using a transport API adapter.
  2. User selects their Ledger device and consents to connect.
  3. A secure channel is established and a session identifier is created.
  4. Operations (e.g., sign) are requested; each requires explicit user confirmation on the device.
  5. Session ends on disconnect or after an inactivity timeout.

Transport adapters

WebUSB

Fast, wired connection with high reliability on supported browsers. Requires HTTPS and a secure origin.

WebHID

Lightweight HID support—useful for integration with certain OS/device combos.

Bluetooth LE

Wireless option for mobile and some desktop environments (requires pairing and BLE permissions).

Fallback

Fallback to QR/Companion app flow when browser transport support is unavailable.

Implementation guide

This section offers concrete code patterns and recommended APIs for implementing the Browser to Device Connector. Keep UI and transport logic separated.

Example: establish session (pseudo-code)

// Pseudo-code: connect and open session
async function connectLedger(adapter){
  const device = await adapter.requestDevice();
  const session = await adapter.openSession(device);
  // session holds an opaque sessionId and transport handle
  return session;
}

Security notes

  • Never cache user private keys in browser storage. All private material must remain in device secure element.
  • Use short-lived session identifiers and rotate them on reconnection.
  • Log events with correlation IDs, but do not log signatures or private key material.

UX patterns

Present clear, progressive disclosure. Show step-by-step instructions on-screen and reflection of device messages. Avoid buried system prompts.

Operational checklist

  • Confirm browser support matrix (Chrome/Edge for WebUSB; updated WebHID where available).
  • Test across OS variations: macOS, Windows, Linux, mobile browsers.
  • Design fallback (QR code + companion app) for unsupported browsers or devices.
  • Plan help flows with copy/paste safe logs for support.

Monitoring

Emit events for connection attempts, failures, transports selected, and key actions like signing. Store only non-sensitive telemetry.

Developer notes

  1. Wrap transport calls with retries and exponential backoff.
  2. Surface device messages exactly as the device reports them; do not reorder important warnings.
  3. Support 'simulate device' mode for local testing with CI.

Common errors & fixes

Permission denied: instruct the user to check the browser prompt and try again.

Device not found: check cable, power, and that the device is unlocked.

Feature cards & Roadmap

User consent UI

Clear modal flows for requesting permissions and requests to sign operations.

Retry & offline handling

Graceful handling of device disconnects and queued requests for reconnection.

Companion app interoperability

Seamless handoff between web and mobile companion when direct transports are not available.

Analytics & support tooling

Support tools for collecting anonymized session telemetry to help resolve issues faster.

Detailed content (expanded)

The following long-form content provides developer-focused explanations and copy the product team can use in help centers, release notes and developer docs.

Introduction

This section covers historical context and motivation for the connector.

Modern web-wallets and dApps need a secure bridge between ephemeral browser contexts and cryptographic hardware like Ledger devices. In-browser capabilities have matured—WebUSB, WebHID and Web Bluetooth enable direct communication—but those channels must be used carefully. This connector enforces the principle that user private keys and signing approvals always remain on the hardware device, while the browser coordinates actions and displays informative prompts to the user.

Detailed flow

1) User clicks "Connect Ledger" in the web app.
2) App selects a transport adapter (for example, WebUSB).
3) The adapter calls the browser permission API and presents a system permission dialog. The user selects a device.
4) On successful connection, the adapter opens a secure channel and the app receives a session token (opaque).
5) The app requests operations from the session (e.g., sign transaction). Each operation prompts the user on-device to confirm. The device returns signed data only after user confirmation.
6) The app verifies signatures server-side or locally before proceeding.

Security deep-dive

Threat model: hostile web page, man-in-the-middle on USB host, compromised browser extension.

Mitigations include: strict origin checks, ephemeral sessions, explicit device prompts, and not relying on browser storage for secrets. Additionally, the device enforces PIN and passphrase protection and displays canonical transaction data to the user, which prevents malicious apps from silently signing transactions.

UX copy suggestions

Use short instructive copy for each step. Example: 

Step 1: Connect your Ledger
- Unlock your Ledger device and open the Ledger Live or appropriate app.
- Choose 'Connect' in this browser dialog.
- Approve the connection on your device.

Step 2: Approve actions
- Review the transaction details displayed on your Ledger.
- Confirm to sign, or decline to cancel.

Step 3: Disconnect
- When finished, disconnect the device physically or click 'Disconnect' in the site UI.

Conclusion

The Browser to Device Connector is a security-first, user-friendly bridge enabling secure, auditable interactions between web apps and Ledger hardware. It reduces friction while preserving the device's role as the single source of truth for private keys and approvals.

Next steps

  • Finalize transport adapters and test across the supported browser matrix.
  • Run a security review and threat modeling session.
  • Prepare a help center article and in-product guided flow.

Thank you — ready to prototype, iterate, and ship.