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SiteGuardian vs Mozilla Observatory

Free HTTP security header scanner from Mozilla

Based on public documentation as of 2026-04-15.

SiteGuardian

EU-hosted continuous security, compliance & monitoring platform

Scope: TLS + DNS + email + headers + accessibility + cookies + compliance

Mozilla Observatory

HTTP response headers + basic TLS

Pricing: Free, no account required

Visit their site →

Feature-by-feature

Each row verified against the competitor's public documentation.

Capability Mozilla Observatory SiteGuardian
HTTP security headers score Yes Yes
Subresource Integrity (SRI) audit Yes Yes
Mixed-content detection Yes Yes
TLS depth (cipher suites, OCSP…) Partial Yes
TLS 1.3 0-RTT (early_data) detection No Yes
DNS / CAA / DNSSEC No Yes
Nameserver redundancy (RFC 2182) No Yes
Email authentication (SPF/DKIM/DMARC/BIMI) No Yes
MTA-STS + TLS-RPT No Yes
Accessibility (WCAG 2.2 / EAA) No Yes
Cookie / GDPR consent scanner No Yes
Continuous monitoring No Yes
EU-hosted (GDPR-friendly)

Observatory runs on Mozilla infrastructure (US/global).

No Yes
Compliance mapping (NIS2, GDPR, DORA) No Yes

When Mozilla Observatory is the better choice

We'd rather be honest than waste your time.

A quick pass/fail grade for the HTTP security headers on a single page.

  • You want a simple A+/F grade for HTTP headers without signing up.
  • You're teaching students about web-security basics.
  • You don't need monitoring, DNS, email or compliance output.

When SiteGuardian is the better choice

  • You want continuous monitoring and alerts, not one-off scans.
  • You need EU data residency and GDPR-by-design processing.
  • You need TLS + DNS + email + headers + accessibility + cookies in one report.
  • You need findings mapped to NIS2, GDPR, DORA, DSA, EAA, CRA articles.
  • You want to benchmark your score against 700k EU sites.

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This comparison is based on publicly available documentation. Product names and trademarks belong to their respective owners. If you spot an inaccuracy, please let us know via contact.