Content Security Policy and Security Headers
CSP, X-Frame-Options, HSTS, and helmet.js — hardening your application with HTTP security headers
Your application can be perfectly coded — no SQL injection, no XSS in your templates, proper authentication everywhere — and still be vulnerable because of missing HTTP headers. Security headers are the seatbelts of web development. They don't prevent crashes, but they dramatically reduce the damage when something goes wrong.
Most AI-generated applications ship with zero security headers. Not because they're hard to add, but because LLMs don't think about the HTTP transport layer when generating application code. This lesson fixes that.
Why Headers Matter
When a browser loads your application, it makes decisions about what to trust, what to execute, and what to block. By default, those decisions are extremely permissive. The browser will:
- Execute any inline script
- Load resource
This lesson is part of the Guild Member curriculum. Plans start at $29/mo.