Your security scanner just came back with 6 flagged items.

All missing HTTP headers.

You did what any reasonable developer does: Googled each one, copy-pasted the recommended config, and shipped a fix in 20 minutes. Job done. Security score green. PR merged.

You also probably shipped at least two of them wrong.

Here is the thing nobody tells you about HTTP security headers: knowing what to add is the easy part. Understanding why it matters, when it actually doesn't, and how a misconfigured one breaks your app in production — that's where most developers fall short.