A single layer of defense is like wearing armor with no pants… still vulnerable.

When you secure a web application, you shouldn’t pour all your efforts into just one layer, whether it’s the network, the frontend, the backend, authentication, etc.

Modern threats cannot be stopped with just one layer. They don’t knock politely at the front door, but look for side windows, back doors, and unpatched cracks. They do not target just one area, they target different things, and security measures are often made to protect against a specific kind of threat. For example, encrypting your communication using TLS will protect all your communication from eavesdropping, but it does nothing to protect against other threats.

You do not want one layer that tries to be everything, rather, you want several layers that each focus on a different aspect and do it very well. You want specialists, not a jack of all trades but a master of none.

Real resilience doesn’t come from any one layer, it comes from defense in depth, i.e., having several well-maintained layers of defense. You need to protect everything, from servers, networks, databases, deployments, endpoints, third-party services, and people.

Some general advice:
✅ Limit the blast radius: Use the principle of least privilege, isolate critical systems, and segment your networks
✅ Keep it simple: one layer is weak, but overcomplicating your security can introduce new risks
✅ Only add new layers if they strengthen your security in an additional way without overly adding complexity.
✅ Train your teams: Security is complex, your teams should understand what the layers do and how to configure them properly

No single shield is enough. Cover your bases, put on some pants.