Permissions

Permissions Overview

At its core, permissions 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 permissions pays off across the whole codebase: fewer surprises, easier testing, and smoother onboarding. The snippet below is a solid starting point.

function requireRole(role) {
  return (req, res, next) => {
    if (req.user?.role !== role) {
      return res.status(403).json({ error: 'Forbidden' });
    }
    next();
  };
}

app.delete('/users/:id', requireRole('admin'), deleteUser);

Authorization middleware checks the authenticated user's role before allowing an action.

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

Authentication Cheatsheet

Quick authentication reference related to permissions.

How Permissions Works

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

Authorization middleware checks the authenticated user's role before allowing an action.

• 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 Permissions

Security is the whole point of permissions. 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 permissions.
• Leaving permissions untested, so regressions slip into production.
• Over-engineering permissions before you actually need the extra flexibility.
• Ignoring documentation, which makes permissions hard for the next developer to change.

Key Takeaways

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