Trezor Suite® – Developer Portal: Secure Integration Guide

Overview

This guide explains secure integration patterns for connecting applications to Trezor Suite® Developer APIs and SDKs. It focuses on architecture, authentication, device interaction, transaction signing, key management, and production hardening — emphasising the principle of least privilege and user safety.

Goals

• Integrate with Trezor Suite in a way that minimises attack surface
• Provide clear developer patterns for signing, verification and recovery
• Ensure auditability and compliance with user consent flows

Who should read this

Frontend engineers, backend engineers, security architects, and SDK authors building wallet integrations or custody solutions.

Prerequisites

• Familiarity with cryptographic primitives (ECDSA/Ed25519, hashing)
• Understanding of hardware wallet concepts and user consent
• Development environment with HTTPS and Content Security Policy support
• Access to Trezor Suite Developer SDKs and local test devices (emulator or hardware)

Security-first checklist

Architecture & Integration Patterns

Recommended topology

Treat Trezor Suite interactions as a user-mediated cryptographic operation. Keep private key material isolated to the device — your server should never hold raw private keys.

Typical flow

1. User opens your app and requests a transaction or a message signing
2. Your app prepares the canonical payload and displays human-readable details
3. The app requests the Trezor device to sign the payload via the SDK or native bridge
4. User verifies and approves the action on the physical device
5. Signed payload returns to the app, which transmits it to the backend or blockchain

Separation of concerns

Design your UI to show precise, minimal transaction information — do not rely on cryptic or truncated data. Separate display logic from signing logic and ensure all user-facing strings are explicit and localised.

Authentication & Authorization

Device-level confirmation

Every sensitive operation must require explicit device confirmation. This prevents malware from silently signing transactions.

OAuth & API keys (backend)

If your integration exposes server-side endpoints, authenticate requests with short-lived tokens (OAuth2/JWT with short TTLs). Scope tokens tightly: separate signing, metadata, and read-only scopes.

Client-side constraints

• Enforce secure contexts (HTTPS and secure cookies)
• Use feature-detection to ensure the bridge (or WebUSB/WebHID) is available before prompting users

Signing Workflows

Canonical payloads

Canonicalise transaction payloads to a deterministic format before sending them to the device. This reduces ambiguity and prevents signing of unintended data.

User-readable breakdown

Display amount, destination, network fee, and any metadata clearly. Encourage users to confirm on-device values against the UI.

Non-repudiation

Log signed transaction IDs, timestamps, and device fingerprinting info (e.g., firmware version) for audits — never log private keys.

// Pseudocode: request signature from device
const payload = buildCanonicalTx(tx);
const signature = await trezor.sdk.sign(payload);
sendToNetwork(signature);
          

Secure Key Management

Never export private keys

Hardware wallets are most secure when private keys remain on-device. Avoid implementing any service that requests private key export.

Backup & recovery

Rely on canonical recovery seeds and follow best practices: encourage users to write down their recovery phrase, keep it offline, and not store it digitally.

Testing & Staging

Local emulator and testnets

Use device emulators and blockchain testnets extensively. Automate end-to-end tests that simulate user confirmations and device flows.

Fuzzing & negative tests

Fuzz transaction fields and simulate malformed payloads to ensure the device and your app reject invalid inputs gracefully.

Hardening for Production

• Use CSP with strict script-src and connect-src directives
• Enable HTTP Strict Transport Security (HSTS)
• Minimise third-party scripts and audit dependencies
• Monitor firmware versions and disallow outdated devices if security vulnerabilities are known

Observability & Auditing

Capture detailed logs for developer troubleshooting while ensuring logs never contain sensitive material. Record the following non-sensitive fields:

• Operation type (sign, verify, list-accounts)
• Timestamp (ISO 8601)
• Device model and firmware version (user-supplied via SDK call)
• Transaction hash or signature fingerprint

Developer Experience Tips

• Provide clear, human-readable confirmation screens with high contrast and large fonts
• Offer a step-by-step integration README and runnable examples
• Provide SDK wrappers for common languages (JS/TS, Python, Go) to reduce integration mistakes

FAQ

Q: Can my server sign on behalf of users?

A: Only if users explicitly give consent and you never expose private keys. Prefer device-only signing for maximum security.

Q: How should I support firmware updates?

A: Notify users of available updates and surface the firmware version. Never auto-apply updates without explicit user consent on the device.

Q: What user education is recommended?

A: Teach users about seed safety, phishing resistance, and verifying transaction details on-device.

Integration Checklist (Pre-Launch)