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Security report for joinmastodon.com

Mastodon gGmbH · Technology · Germany

Low risk. 3 critical or high findings in Security headers and GDPR outside view.

Security score

78/100

Risk levelLow

0–100, higher is better. How it is calculated

Mastodon gGmbH operates joinmastodon.org, a leading decentralized social media platform emphasizing user control, privacy, and open-source principles. The platform enables users to join or host independent servers, fostering a federated social network free from corporate control and advertising. The business model is non-profit, sustained by public donations and sponsorships, positioning Mastodon as a key player in the decentralized social media space. Technically, the website is built on modern web technologies including React and Next.js, delivering a fast, mobile-optimized, and accessible user experience. Hosting and CDN services are provided by reputable partners such as Fastly, ensuring reliable performance. The site demonstrates good SEO practices and clear navigation, supporting a broad international audience with multiple language options. From a security perspective, the site enforces HTTPS and employs domain transfer protections, though DNSSEC is not enabled. No critical vulnerabilities or exposed sensitive data were detected. However, the absence of explicit security policies, vulnerability disclosure, and cookie consent mechanisms suggests areas for improvement. The WHOIS data is consistent with the organization's identity and domain age, reinforcing legitimacy. Overall, joinmastodon.org presents a trustworthy, professional, and privacy-conscious platform with strong community and technical foundations. Strategic enhancements in security transparency and privacy compliance would further strengthen its posture.

Scanned

NIS2 and GDPR posture

GDPR outside view
53/ 100 · Medium
Checks completed
7of 7

NIS2 Art. 21(2)

  1. (a) Risk analysis and security policies: Not visible from outside
  2. (b) Incident handling: One indicator
  3. (c) Business continuity, backups and crisis management: Not visible from outside
  4. (d) Supply chain security: Not visible from outside
  5. (e) Secure acquisition, development and maintenance, including vulnerability handling: Partly checked
  6. (f) Assessing the effectiveness of security measures: Not visible from outside
  7. (g) Cyber hygiene and security training: Not visible from outside
  8. (h) Cryptography and encryption: Partly checked
  9. (i) HR security, access control and asset management: One indicator
  10. (j) Multi-factor authentication and secured communications: Not visible from outside

This scan rated NIS2 with an earlier keyword method that is no longer shown; rescan for the per-article view. Risk management, continuity, supply chain, training, MFA, management oversight (Art. 20) and incident reporting (Art. 23) need internal evidence, and Guard cannot tell whether NIS2 applies to this organisation.

GDPR is indicative only, based on publicly visible signals: Articles 7, 12, 13 and 32 of Regulation (EU) 2016/679 and Article 5(3) of the ePrivacy Directive. Not a certification or legal assessment.

Priority findings

3 findings rated critical or high. Fix these first.

  1. Security headers

    Security headers are instructions your web server sends to every visitor’s browser. Missing ones leave visitors more exposed to attacks such as clickjacking and injected scripts.

    • High

      Missing X-Frame-Options header

      Prevents clickjacking attacks

      What to do: Add "X-Frame-Options: DENY" or "X-Frame-Options: SAMEORIGIN"

  2. GDPR outside view

    These are the privacy signals visitors and data protection authorities look for under GDPR.

    • High

      No Cookie Policy found

      GDPR requires clear information about cookie usage

      What to do: Add a dedicated cookie policy explaining cookie usage and purposes

    • High

      No Cookie Consent Banner found

      GDPR requires explicit consent for non-essential cookies

      What to do: Implement a cookie consent banner that appears on first visit

Need hands-on remediation? Email guard@offseq.com

Keep watching joinmastodon.com

This scan found 18 issues across 6 checks. Monitoring re-runs those checks daily, emails you when something material changes and records each fix, so you can show progress.

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  • TLS certificates and expiry
  • DNS records
  • SPF, DKIM and DMARC
  • Security headers
  • GDPR and NIS2 posture
  • Exposed services
  • Third-party trackers
  • Security score drift

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Results by check

Each check with its score, findings and the evidence it collected.

How this score is calculated

The security score runs 0–100, higher is better. It is the plain average of the security checks that completed in this scan, each counted equally. A check that could not run is left out: it counts neither as a pass nor as a fail.

Counted in this score

SSL/TLS
95
Security headers
65
Email security
75
DNS health
80
Network security
100
GDPR outside view
53
Average
78

Not counted

  • NIS2 outside view: Re-weights evidence from the TLS, email, DNS, network and hygiene checks, so counting it would count that evidence twice. Shown on its own.
  • OffSeq Observations: An AI reading of the site, useful context but not reproducible evidence. Shown on its own.

Findings that cap the score at 49

Each of these is serious on its own, so while any is present the site cannot rate better than high risk, however good the other checks are.

  • The certificate is not trusted by browsers
  • The website is not served over HTTPS
  • A database, remote desktop, file-sharing or Telnet service is reachable from the internet
  • The page loads a script from a compromised source
  • The domain registration has expired
  • SPF authorises every server to send mail as the domain

Partial scans

When the site blocks Guard or most checks cannot run, the score covers only the checks that ran (usually DNS and email), is capped at 75 and is shown as partial, without a risk level.

Risk levels

  • Critical0–25
  • High26–49
  • Medium50–75
  • Low76–100

Technical appendix

Business context, site observations and technical notes gathered during the scan, and the standards behind each reference.

Business context

Business profile

Mastodon gGmbH occupies a unique niche as a non-profit provider of decentralized social media infrastructure. Its competitive advantage lies in its open-source nature, federated architecture, and community-driven moderation model. Revenue streams primarily come from donations via Patreon and direct payments through Stripe. The target audience includes privacy-conscious users, developers, and communities seeking alternatives to centralized social networks. The partnership ecosystem includes hosting providers, payment processors, and technology sponsors, reflecting a collaborative operational model. Growth indicators include a broad multilingual website presence and active community testimonials. The company maintains independence and transparency, avoiding advertising and data monetization.

Security posture

The website demonstrates a mature security posture with enforced HTTPS, domain transfer lock, and no visible security misconfigurations or vulnerabilities. However, the lack of DNSSEC and absence of published security policies or incident response contacts indicate gaps in formal security governance. No security.txt or vulnerability disclosure program is present, which could hinder coordinated vulnerability management. Privacy compliance is strong with a comprehensive privacy policy, but cookie consent mechanisms are missing. The site does not expose sensitive data or use vulnerable libraries. Overall, the security culture appears community-focused but could benefit from formalized policies and transparency.

Recommendations

  1. Enable DNSSEC to enhance domain name system security and prevent spoofing.
  2. Publish a dedicated security policy and incident response plan including contact channels.
  3. Implement a vulnerability disclosure program and provide a security.txt file.
  4. Add a cookie consent banner or mechanism to comply with privacy regulations fully.
  5. Incorporate additional security headers such as Content-Security-Policy and X-Frame-Options.
Site observations

Automated reading of the public site. Ratings are indicative.

Business

Company
Mastodon gGmbH
Description
Mastodon is a radically different, free and open-source decentralized social media platform that puts social networking back in the hands of the people.
Key services
Decentralized social networking, Hosting Mastodon servers, Providing apps and resources, Community moderation tools
Content quality
excellent
Branding
consistent

Technology

Stack
React, Next.js, JavaScript, CSS
Frameworks
Next.js
Performance
fast
Mobile
excellent
Accessibility
good
SEO
good

Security

Observed score
80/100
Good practices seen
  • HTTPS enforced
  • ClientTransferProhibited domain status
  • No exposed sensitive data in HTML

Analytics and tracking

Tracking level
minimal
Privacy practices
excellent

Advertising

Transparency
excellent

Site quality

Design
excellent
User experience
excellent
Content relevance
excellent
Navigation
excellent
Professionalism
excellent
Trustworthiness
high

Key observations

  1. Website is fully accessible with no blocking or WAF challenges.
  2. Strong emphasis on decentralization, open source, and user control.
  3. No explicit contact emails or phone numbers publicly listed; contact via form.
  4. No cookie consent banner detected despite likely use of cookies.
  5. No explicit terms of service page found.
  6. Multiple external trusted partners and sponsors listed.
  7. No security.txt or vulnerability disclosure policy found.
  8. WHOIS data is consistent and domain is well maintained with long expiry.
  9. Website uses modern web technologies and is mobile optimized.
  10. No advertising or tracking scripts detected in HTML content.
Technical notes

Notes

The website leverages a modern React and Next.js framework, enabling server-side rendering and optimized performance. The use of Fastly CDN and sponsorship from technology partners supports scalability and reliability. The site is fully responsive with excellent mobile optimization and accessibility features. SEO is well addressed through meta tags and Open Graph data. No CMS is detected, indicating a custom or framework-based solution. The technical stack is current with no signs of legacy technology or technical debt. Opportunities exist to enhance security headers and formalize privacy compliance mechanisms.
Standards and sources

Reference chips under each finding point to the standard, regulation or specification the finding relates to. They are taken from the official datasets below and mapped conservatively: a finding with no defensible link shows none. NIS2 and GDPR references mark where a finding is relevant evidence, not a compliance verdict. Implementing Regulation (EU) 2024/2690 binds digital infrastructure and digital service providers; for other entities it is the most detailed public reading of the Article 21 measures. WCAG, EN 301 549, European Accessibility Act and Web Accessibility Directive references name the requirement an automated accessibility rule relates to; they are not a conformance verdict.

Retrieved 2026-10-25

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