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Security report for tlon.io

Tlon · Technology · United States

Medium risk. 5 critical or high findings in Security headers, GDPR outside view and 1 other check.

Security score

67/100

Risk levelMedium

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

Tlon is a technology company focused on building well-crafted software, primarily the Tlon Messenger app, which emphasizes user ownership of data and privacy. The company operates from the US and has been established since 2013. Their market position is niche, targeting users who value privacy and control over their digital communications. The website reflects a modern technical infrastructure using the Astro framework, Cloudflare hosting, and integrates Google Analytics for user insights. Mobile optimization and user experience are strong points, with a clean, professional design and clear messaging. Security posture is adequate with HTTPS and domain transfer protections, but lacks advanced security headers and published security policies. Privacy compliance is basic, with a privacy policy present but no cookie consent mechanism despite tracking usage. Overall, the site is trustworthy but could improve transparency and security practices.

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

5 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"

    • High

      Missing Content-Security-Policy header

      Controls resources the browser is allowed to load

      What to do: Implement a Content-Security-Policy appropriate for your application

      • ASVS V3.4.3
      • OWASP Secure Headers: OWASP Secure Headers Project recommends Content-Security-Policy: default-src 'self'; form-action 'self'; base-uri 'self'; object-src 'none';…

  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

  3. SSL/TLS

    TLS encrypts the connection and proves the site is really yours. Weak or expiring certificates trigger browser warnings and put traffic at risk.

    • High

      Weak SSL Key Length

      SSL certificate uses 256-bit key, which is considered weak

      What to do: Use at least 2048-bit RSA or 256-bit ECC key

      • CWE-326
      • OWASP A04:2025
      • Mozilla TLS: Mozilla Server Side TLS 6.0 intermediate: rsa_key_size 2048

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

Keep watching tlon.io

This scan found 24 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.

Daily monitoring

Recommended

€25per month

  • 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
75
Security headers
30
Email security
70
DNS health
75
Network security
100
GDPR outside view
53
Average
67

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

Tlon's business model centers on software development and distribution of a privacy-focused messaging app. Their competitive advantage lies in cryptographic ownership of user data and an open-source approach, appealing to privacy-conscious users. The company targets general consumers interested in secure, distraction-free communication tools. Growth indicators include active content updates and a waitlist for app access. The partnership ecosystem is limited publicly, with no explicit partner domains identified. The company maintains a consistent brand and professional online presence, supporting its credibility in the technology sector.

Security posture

The website demonstrates a moderate security maturity level with HTTPS enforced and domain transfer protections. However, the absence of DNSSEC, security headers, and published incident response or vulnerability disclosure policies indicates gaps in security best practices. No exposed sensitive data or vulnerable libraries were detected. The use of Google Analytics without a cookie consent banner suggests partial privacy compliance. The lack of a security.txt file or dedicated security contact channels limits incident response readiness. Overall, the security posture is functional but could benefit from enhancements to align with industry standards and regulatory requirements.

Recommendations

  1. Enable DNSSEC to improve domain name system security.
  2. Implement and display a cookie consent mechanism to comply with privacy regulations.
  3. Add security headers such as Content-Security-Policy, X-Frame-Options, and Strict-Transport-Security.
  4. Publish a security policy and incident response contact information to enhance transparency and trust.
  5. Consider creating a vulnerability disclosure program or security.txt file to facilitate responsible reporting.
Site observations

Automated reading of the public site. Ratings are indicative.

Business

Company
Tlon
Description
Tlon exists to build exceptionally well-crafted software for people’s everyday lives.
Key services
Tlon Messenger app, Software development, Open source software
Content quality
good
Branding
consistent

Technology

Stack
Astro framework, Cloudflare DNS, Google Analytics, Partytown for script offloading
Frameworks
Astro
Performance
fast
Mobile
excellent
Accessibility
good
SEO
good

Security

Observed score
75/100
Good practices seen
  • HTTPS enforced
  • Domain status clientTransferProhibited

Analytics and tracking

Services
Google Analytics
Tracking level
moderate
Privacy practices
basic

Advertising

Transparency
basic

Site quality

Design
good
User experience
good
Content relevance
good
Navigation
good
Professionalism
good
Trustworthiness
moderate

Key observations

  1. Website uses modern Astro framework with client-side hydration
  2. No explicit contact emails or phone numbers found on main site
  3. Privacy and terms pages present but privacy policy lacks explicit GDPR compliance statements
  4. No cookie consent banner detected despite use of Google Analytics
  5. Site promotes open source software and user data ownership
  6. No security.txt or vulnerability disclosure policy found
  7. No explicit security or incident response policies published
Technical notes

Notes

The website is built using the Astro framework, leveraging modern JavaScript and client-side hydration techniques. Hosting is provided via Cloudflare, ensuring fast content delivery and DNS management. Google Tag Manager and Google Analytics are used for tracking, with Partytown employed to offload third-party scripts for performance optimization. The site is mobile-optimized with responsive design and good accessibility features. No CMS was detected, indicating a custom or static site approach. Performance is fast with well-structured meta tags supporting SEO. Technical risks include lack of DNSSEC and missing security headers, which could expose the site to certain attack vectors. Overall, the technical infrastructure is modern and well-implemented but could be improved with enhanced security configurations.
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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