10 Best Website Security Scanners in 2026 (Free & Paid)

"Security scanner" covers a wide range of tools - free header checkers, SSL testers, full vulnerability scanners, and everything in between. Here's what each of these ten actually checks, starting with our own, so you pick the right one instead of the first one in a search result.

What Kind of Scanner Do You Actually Need?

Before the list, it helps to know which category you're in:

• Configuration checkers - do you have the right headers, cookies, and TLS settings? Fast, free, no false-positive risk.
• Vulnerability scanners - is there an actual exploitable issue (XSS, injection, exposed admin panel)? Slower, deeper, usually paid.
• Monitoring - did something change since the last scan? Ongoing, alert-driven.

Most sites need the first category running continuously and the second one occasionally. Few need the third from day one.

The List

1. Scanverra

Our own security scanner, so weigh this placement accordingly - but here's why it leads this list. It covers the configuration-checker category above - headers, cookie flags, TLS/SSL setup, DNS records, exposed secrets, and common CSRF gaps - in the same ~30-second scan as the rest of Scanverra's audit, with a plain-English explanation of each finding instead of a raw header dump. It won't replace OWASP ZAP or Nessus for active exploitation testing, but for the "are my basics actually covered" question most sites need answered continuously, it's built to be the fast, free first pass.

Best for: a fast, ongoing check that your security fundamentals haven't drifted, alongside the rest of your Scanverra audit.

2. Mozilla Observatory

A free, well-respected header and configuration checker built by Mozilla. It grades your CSP, HSTS, and other security headers, explains what each one does, and links out to the relevant documentation. No account required.

Best for: a fast, credible first pass on header configuration.

3. SecurityHeaders.com

A narrower, faster equivalent - paste a URL, get a letter grade on your security headers in seconds. Less explanatory depth than Observatory, but hard to beat for speed.

Best for: a 10-second header check with zero setup.

4. Qualys SSL Labs

The standard tool for TLS/SSL configuration testing - certificate validity, protocol support, cipher strength, and known vulnerabilities like protocol downgrade attacks. If your site handles anything sensitive, this is worth running once and then again after any server/CDN change.

Best for: verifying your HTTPS setup is actually configured correctly, not just present.

5. Sucuri SiteCheck

A free malware and blacklist scanner - it checks whether your site is currently flagged by Google Safe Browsing or other blacklists, and scans for known malware signatures and injected spam. More useful for "is my site already compromised" than proactive hardening.

Best for: checking whether a site has already been compromised.

6. Detectify

A paid, automated vulnerability scanner that also does external attack-surface monitoring - it finds subdomains and exposed assets you may have forgotten about, not just the URL you point it at. Backed by a crowdsourced ethical-hacker research team feeding in new checks.

Best for: ongoing external attack-surface monitoring, not a one-off check.

7. Intruder

Continuous vulnerability scanning positioned for teams without a dedicated security function - automatic scans on new CVE disclosures, prioritized results, and less noise than a raw scanner output. Paid, with a real onboarding/support layer.

Best for: teams who want vulnerability scanning without hiring for it.

8. OWASP ZAP

A free, open-source dynamic application security testing (DAST) tool maintained under the OWASP umbrella. Genuinely powerful - it can actively probe for injection and XSS, not just check configuration - but it has a real learning curve and is built more for security practitioners than a quick self-serve check.

Best for: teams with security engineering time to actually drive the tool.

9. Tenable Nessus

An enterprise-grade vulnerability scanner with one of the largest plugin/signature libraries in the industry. Built for infrastructure and network scanning as much as web applications specifically - genuinely thorough, genuinely overkill for a single marketing site.

Best for: organizations already running broader infrastructure vulnerability management.

10. Pentest-Tools.com

A web-based toolkit bundling recon, subdomain enumeration, and a range of individual vulnerability checks behind one interface, with a usable free tier before the paid plans. A reasonable middle ground between a single-purpose checker and a full enterprise scanner.

Best for: a broader one-off recon pass without installing anything.

Which One Should You Actually Use?

Start with a free configuration check - Scanverra, Mozilla Observatory, or SecurityHeaders.com will all catch missing headers and TLS misconfiguration in seconds. If that comes back clean and you handle sensitive data, layer in Qualys SSL Labs for a deeper TLS check and consider OWASP ZAP or a paid vulnerability scanner for active testing. Most sites overinvest in the second category before they've nailed the first.