Public and Private Claims

Public and Private Claims Overview

At its core, public and private claims is about doing one thing well inside your authentication project. Once you understand the pattern, you can apply it consistently across features and teams.

Good public and private claims pays off across the whole codebase: fewer surprises, easier testing, and smoother onboarding. The snippet below is a solid starting point.

import jwt from 'jsonwebtoken';

// issue a signed access token
const token = jwt.sign(
  { sub: user.id, role: user.role },
  process.env.JWT_SECRET,
  { expiresIn: '15m' },
);

// verify it on protected routes
const payload = jwt.verify(token, process.env.JWT_SECRET);

A JWT encodes signed claims so the server can trust the token without a session lookup.

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

Authentication Cheatsheet

Quick authentication reference related to public and private claims.

How Public and Private Claims Works

Public and Private Claims is part of proving who a user is and what they are allowed to do. Authentication verifies identity, while authorization decides access — and public and private claims plays a specific role in that flow.

A JWT encodes signed claims so the server can trust the token without a session lookup.

• 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 Public and Private Claims

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

Common Mistakes

• Copying public and private claims snippets without understanding what each line does.
• Skipping error handling and edge cases when wiring up public and private claims.
• Leaving public and private claims untested, so regressions slip into production.
• Over-engineering public and private claims before you actually need the extra flexibility.

Key Takeaways

• Public and Private Claims is a core part of working effectively with authentication.
• Start small and keep public and private claims focused on a single responsibility.
• Apply consistent patterns so public and private claims scales across your project.
• Test and document public and private claims to keep it maintainable over time.