Device Trust

Device Trust Overview

Device Trust lets you structure authentication work so it stays readable, testable, and easy to scale. Instead of ad-hoc code, you follow a clear pattern that other developers can recognise immediately.

The key is to keep device trust focused and predictable. Start from the minimal example here, then layer in only the complexity your feature actually needs.

import express from 'express';
import jwt from 'jsonwebtoken';

const app = express();
app.use(express.json());

function authenticate(req, res, next) {
  const token = req.headers.authorization?.replace('Bearer ', '');
  try {
    req.user = jwt.verify(token, process.env.JWT_SECRET);
    next();
  } catch {
    res.status(401).json({ error: 'Unauthorized' });
  }
}

Authentication middleware verifies the caller's identity before protected handlers run.

Device Trust Example

// verify the caller on every protected request
function authenticate(req, res, next) {
  const token = req.headers.authorization?.replace('Bearer ', '');
  req.user = verifyToken(token); // throws if invalid
  next();
}

• Start from a minimal Device Trust example and grow it only as needed.
• Keep configuration explicit so Device Trust behaves the same in every environment.
• Name things clearly so teammates understand your Device Trust at a glance.
• Add tests around Device Trust early to lock in expected behaviour.

Authentication Cheatsheet

Quick authentication reference related to device trust.

How Device Trust Works

Device Trust is part of proving who a user is and what they are allowed to do. Authentication verifies identity, while authorization decides access — and device trust plays a specific role in that flow.

Authentication middleware verifies the caller's identity before protected handlers run.

• Never store or log plain-text passwords or secrets.
• Prefer short-lived tokens with refresh over long-lived ones.
• Always send credentials over HTTPS.
• Fail closed: deny access when anything is uncertain.

Security Guidance for Device Trust

Security is the whole point of device trust. Small mistakes — weak hashing, tokens in localStorage, missing rate limits — are exactly what attackers look for, so follow proven defaults.

Common Mistakes

• Skipping error handling and edge cases when wiring up device trust.
• Leaving device trust untested, so regressions slip into production.
• Over-engineering device trust before you actually need the extra flexibility.
• Ignoring documentation, which makes device trust hard for the next developer to change.

Key Takeaways

• Device Trust is a core part of working effectively with authentication.
• Start small and keep device trust focused on a single responsibility.
• Apply consistent patterns so device trust scales across your project.
• Test and document device trust to keep it maintainable over time.