Hullwise vs Mozilla Observatory
The MDN HTTP Observatory, formerly Mozilla Observatory, mainly checks HTTP headers and related settings such as cookies, the redirect to HTTPS and SRI, with a score and a grade.
Hullwise requests the page once and reads security headers, certificate, email protection, software versions, the served HTML and the JavaScript files the page includes. Below is where that overlaps with Mozilla Observatory.
Checks side by side
Where Mozilla Observatory does more, the table says so and highlights it in green. Here that applies to: Security headers.
| Check | Hullwise | Mozilla Observatory |
|---|---|---|
| Security headers | Yes, six headers checked for presence, plus server and technology disclosure | Yes, the core feature, with points per test. Also checks CORS and Cross-Origin-Resource-Policy Mozilla Observatory does more here |
| TLS and certificate in depth | Basics: valid, expiry date, TLS 1.0 or 1.1. No review of cipher suites | No. The TLS and certificate evaluation was removed in 2024. It checks whether the site redirects to HTTPS first |
| SPF and DMARC | Yes, via public DNS, plus MTA-STS or DANE and the limit of 10 SPF lookups | Not mentioned |
| Versions with known vulnerabilities | Yes, detected JavaScript libraries live against OSV.dev, prioritized by CISA KEV (actively exploited) and FIRST EPSS, plus end of support via endoflife.date and insecure WordPress versions via WordPress.org | No, not part of the test according to MDN |
| Technology detection | Yes, with the rules of webappanalyzer (a fork of the Wappalyzer rules) and Retire.js, plus platforms and hosts such as Lovable, Bolt, v0, Replit, Vercel, Netlify and Supabase | Not mentioned |
| Secrets in the HTML | Yes, the same patterns as in the JavaScript files, also in embedded data such as __NEXT_DATA__, plus Google API keys as a notice. We report the type and where it was found, the value only shortened | Not mentioned |
| Keys in the JavaScript files of vibe-coded apps | Yes, 16 types of our own for secret keys and credentials, such as Supabase service_role, OpenAI, Anthropic, Stripe and AWS, plus over 100 providers from the gitleaks rules. We read up to 50 files from the same domain: included files, parts loaded when switching pages, for Next.js the parts of every page, and configuration files such as /config.json that the code fetches on startup. We report the type and where it was found, the value only shortened, for example sk_live_…9f2A, never in full | Not mentioned |
| Third-party scripts without SRI | Yes | Yes |
| Cookies | Yes, Secure and HttpOnly | Yes, secure cookie settings |
| Malware and blocklists | No | Not mentioned |
| Explanation of findings | One or two sentences per finding in English or German, with a link to the fix guide. Without a paid plan, two findings come in full, all of them with Business | Score of up to 145 and a grade from A+ to F |
| API | Yes, with a free key 100 checks per hour and a shortened report, full with Business. No REST API without a key, only MCP | Yes, v2 API. A site can be rescanned at most every 60 seconds |
| MCP for AI agents | Yes, for Claude, ChatGPT, Cursor, Codex and VS Code. Without a key 20 checks per hour and a shortened report, full with Business | Not mentioned |
| Weekly monitoring | Yes, with Business up to 10 domains, with an email as soon as a grade drops | Not mentioned |
| Manual review (audit) | Yes, from €1,500 per application, only after proof of ownership | Not mentioned |
As of October 2026. "Not mentioned" means the Mozilla Observatory pages linked below say nothing about it. The feature may still exist there. What Hullwise checks in detail is described under How we check.
- Source: MDN: HTTP Observatory
- Source: MDN: Introducing the MDN HTTP Observatory
- Source: MDN: Observatory FAQ
- Source: MDN: Tests and scoring
When Mozilla Observatory is the better fit
- You only want to check your headers, with points per test. That is what the Observatory is built for.
- You want CORS and Cross-Origin-Resource-Policy included. We don't check those.
- You already work with the MDN documentation and want the explanations right there.
You can use both tools side by side. Hullwise gives you an overview across six areas; for a single area, Mozilla Observatory takes a closer look.
What your AI agent can do with it
Hullwise has an MCP server. Add it to Claude, ChatGPT, Cursor, Codex or VS Code, and your agent checks sites itself with scan_website and shows what is checked with list_checks. Over MCP, you get 20 checks per hour without a key and 100 with a free key. The REST API always requires a key. Without a paid plan, the API and MCP return two findings in full; with Business, the complete report.
The Observatory has an API that returns grade and score. The MDN pages do not mention an MCP server.
According to MDN, the scan history of every domain is public. Hullwise results are not publicly visible.
What happens after a finding
The Observatory shows score and grade per test. The MDN pages mention no fixing service and no review by people.
At Hullwise, every finding leads to a guide on how to fix it. With Business, we then check up to 10 domains every week and email you as soon as a grade drops (€149 per month). The Security Audit is a manual review that starts only after you prove ownership. It also covers what is not visible from the outside, such as open databases and access permissions. It starts at €1,500 per application.
All trademarks belong to their owners and are not affiliated with Hullwise. Information about Mozilla Observatory is based on its own pages, as of October 2026.
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