---
title: "How to use the free security header checker — Lemwatch Help"
description: "Grade any site's HTTP security headers (CSP, HSTS, X-Frame-Options, Referrer-Policy) instantly."
canonical: "https://lemwatch.com/help/using-the-free-security-header-checker"
source: "https://lemwatch.com"
---

# How to use the free security header checker

> Grade any site's HTTP security headers (CSP, HSTS, X-Frame-Options, Referrer-Policy) instantly.

## Quick answer

 Enter any URL at /tools/security-header-checker to see which headers are set, which are missing, and get an A–F grade with fix suggestions.

## What it checks

- Content-Security-Policy (presence, weak directives)

- Strict-Transport-Security (max-age, includeSubDomains)

- X-Frame-Options / frame-ancestors

- X-Content-Type-Options and Referrer-Policy

- Permissions-Policy and cross-origin isolation headers

## Where to find it in Lemwatch

 Public URL: **/tools/security-header-checker**. Results include copy-paste snippets for nginx, Apache, and Cloudflare Workers.

## How to use it

- Enter your homepage URL.

- Click Grade headers .

- Read the per-header verdict and severity.

- Copy the recommended config snippet for your server.

- Re-test after deploy to confirm the grade improved.

## FAQ

### Why did I get a B when the site looks fine?

 Missing CSP or a wildcard frame-ancestors typically drops the grade one letter. Both are common on WordPress.

### Does this test authenticated pages?

 No — only public URLs. For auth-gated pages, use Lemwatch's authenticated monitoring.

## Related

- Free SSL checker

- Free mixed content checker

- Free Mozilla Observatory scan


## Related

- [Help centre](https://lemwatch.com/help)
- [How to use the free SSL certificate checker](https://lemwatch.com/help/using-the-free-ssl-checker)
- [How to use the free mixed content checker](https://lemwatch.com/help/using-the-free-mixed-content-checker)
- [How to use the free sitemap diff tool](https://lemwatch.com/help/using-the-free-sitemap-diff-tool)
- [Lemwatch pricing](https://lemwatch.com/pricing)