When your website loads, your server sends back two things:

the page content (HTML)
the headers (metadata about how to handle the content)

Headers are small pieces of information sent before the webpage itself. Some are normal (like content type). Others are security-focused.

Why security headers matter

Security headers tell a browser how to behave when it displays your site. This can prevent certain attacks and reduce the risk of your site being used in harmful ways.

Here are a few important ones, explained simply.

X-Frame-Options

This header helps prevent your site from being embedded inside another website.

That matters because of clickjacking.

Clickjacking is a trick where attackers place your site inside an invisible frame and lure people into clicking buttons they did not mean to click.

X-Content-Type-Options

This helps prevent the browser from guessing file types.

That guessing can lead to dangerous behavior where a file is treated like code.

Referrer-Policy

This controls how much information your browser shares when it clicks from one site to another.

A “referrer” is the page a visitor came from.

Strict-Transport-Security (HSTS)

HSTS tells the browser: “Always use HTTPS for this site.”

That helps prevent visitors from accidentally using HTTP.

Content-Security-Policy (CSP)

CSP is one of the most powerful headers.

It controls where scripts and resources are allowed to load from. If an attacker tries to inject malicious JavaScript, CSP can block it.

This is a common defense against XSS.

XSS (Cross-Site Scripting) is when an attacker injects JavaScript into a website so it runs in a visitor’s browser.

What to do with this information

You don’t need to memorize headers.

You need a checklist and a way to verify your site is using them.

SafeSiteScan checks for key security headers and tells you what’s missing so you can improve your trust score and reduce risk.

Security headers are not “extra credit.” They are basic safety rails for modern websites.