Missing headers are invisible without a check
Security headers like HSTS, X-Frame-Options, and CSP don't cause visible errors when absent, so they're easy to miss without an explicit review as part of the launch or handoff process.
Security Header Checker
Check security headers on client websites
Review whether key security headers are present on client websites — HSTS, X-Frame-Options, X-Content-Type-Options, Referrer-Policy, and CSP — as part of your standard website health workflow.
No credit card required · Real server-side header checks · Built for agency website reviews
Example check preview
Website health signals, not live monitoring data
Website reachableok
HTTPS activeok
Response time signalreview
SSL/domain notereview
Risk summaryreview
The Problem
Small misses turn into public failures fast.
Clients expect agencies to catch these issues
Agencies are trusted to review technical details clients cannot check themselves. A missing security header found after launch reflects on the agency's quality of review.
Headers are often lost after platform migrations
Moving a site to a new host, CMS, CDN, or server configuration can silently remove security headers that were previously in place.
How It Works
1
Add your domain
Enter the website, subdomain, or client property you need to protect.
2
MonitorMojo checks it
Run a real reachability, HTTPS/SSL, response time, and configured health check.
3
Review what needs attention
Use the returned signals to decide what to fix before a browser error or complaint.
Features
Website health checks built for the signals teams forget until they hurt.
lock
HSTS check
Review whether HTTP Strict Transport Security is present, which tells browsers to only connect to the domain over HTTPS.
grid_off
X-Frame-Options review
Check whether the header is set to prevent the page from being embedded in iframes by third-party sites.
policy
X-Content-Type-Options signal
Verify whether the header is present to prevent browsers from guessing (sniffing) the MIME type of a response.
share
Referrer-Policy check
Review whether a Referrer-Policy header is set to control how referrer information is shared when users navigate away.
security
Content-Security-Policy note
Check for the presence of a CSP header, which controls which sources browsers are allowed to load content from.
health_and_safety
Overall header summary
Get a combined view of which headers are present, which are missing, and which need review across the checked website.
Who This Is For
Built for teams closest to the website.
Web agencies
Add security header checks to your standard pre-launch, post-migration, or monthly website review workflow.
Freelance developers
Review client sites before handoff to catch missing headers that could come back as an issue after launch.
Website managers
Keep track of security header status across maintained properties so changes to hosting or CDN configuration don't go unnoticed.
FAQ
Questions teams ask before they check website health.
What are security headers?
Security headers are HTTP response headers that instruct browsers on how to handle a website's content. Common ones include HSTS, X-Frame-Options, Content-Security-Policy, X-Content-Type-Options, Referrer-Policy, and Permissions-Policy.
Why do security headers matter for client websites?
Missing or misconfigured headers can leave a site more exposed to common browser-based attack patterns. Agencies that include header checks in their workflow can identify these gaps before they become a client concern or a reported vulnerability.
What is HSTS?
HTTP Strict Transport Security (HSTS) is a header that tells browsers the site should only be accessed over HTTPS. Without it, browsers may allow insecure HTTP connections even when HTTPS is available on the server.
What does X-Frame-Options do?
X-Frame-Options tells browsers whether the page can be embedded in an iframe by another website. Setting it to DENY or SAMEORIGIN helps protect against clickjacking, where a hidden frame tricks users into clicking on something unexpected.
What does X-Content-Type-Options protect against?
The X-Content-Type-Options: nosniff header prevents browsers from guessing the MIME type of a response when the server has declared one. This reduces the risk of certain content injection scenarios.
What is a Content Security Policy (CSP) header?
A Content Security Policy header tells browsers which sources they are allowed to load scripts, styles, images, and other resources from on the page. A well-configured CSP helps reduce the risk of cross-site scripting (XSS) attacks.