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Security report for protonmail.com

Proton AG · Technology · Switzerland

Low risk. 4 critical or high findings in Security headers, GDPR outside view and 1 other check.

Security score

77/100

Risk levelLow

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

Proton AG operates Proton Mail, the world's largest secure email service with over 100 million users, headquartered in Switzerland. The company offers a suite of privacy-focused services including encrypted email, calendar, cloud storage, password manager, VPN, and more, targeting privacy-conscious individuals, journalists, activists, and businesses. Proton's business model is freemium, providing free secure email accounts supported by paid subscription plans with enhanced features. The company is well-positioned in the privacy technology market, emphasizing Swiss privacy laws and open-source transparency. Technically, Proton's website employs modern web technologies including React and Astro frameworks, delivering a fast, mobile-optimized, and accessible user experience. The infrastructure supports multiple platforms including web, desktop, and mobile apps. SEO and content quality are excellent, reflecting a mature digital presence. Security-wise, Proton demonstrates strong practices with HTTPS enforcement, comprehensive security headers, end-to-end and zero-access encryption, and independent audits. However, DNSSEC is not enabled, and explicit incident response contacts or vulnerability disclosure pages are not found, representing minor gaps. Overall, Proton Mail's website and business exhibit high trustworthiness, professionalism, and compliance with privacy regulations such as GDPR. The risk profile is low, with no detected vulnerabilities or suspicious indicators. Strategic recommendations include enabling DNSSEC, publishing a security.txt file, and providing clearer incident response contacts to further enhance security posture and transparency.

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

4 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

  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 Protocols Supported

      Server supports weak protocols: TLSv1.1

      What to do: Disable TLS 1.0, TLS 1.1, and all SSL versions

      • CWE-327
      • OWASP A04:2025
      • ASVS V12.1.1

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

Keep watching protonmail.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.

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
72
Security headers
65
Email security
80
DNS health
90
Network security
100
GDPR outside view
53
Average
77

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

Proton AG holds a strong market position as a leading privacy-focused technology company, leveraging Swiss jurisdiction as a competitive advantage. Its freemium business model balances free user acquisition with paid subscriptions for advanced features. The company targets a diverse audience including individuals valuing privacy, journalists, activists, and enterprises requiring secure communications. Proton's ecosystem includes complementary services like VPN and password management, fostering cross-product adoption. Partnerships with services like Simple Login and Standard Notes expand its privacy portfolio. Growth indicators include over 100 million users and 50,000 business customers. The company maintains a transparent and open-source approach, enhancing credibility and community trust.

Security posture

Proton Mail exhibits a mature security posture with robust encryption technologies ensuring end-to-end and zero-access protection. The website enforces HTTPS and implements multiple security headers to mitigate common web threats. Open-source codebases and independent audits reinforce security transparency. No critical vulnerabilities or exposed sensitive data were detected. However, the absence of DNSSEC and a published security.txt file limits DNS security and vulnerability disclosure clarity. Incident response contact information is not explicitly provided, which could hinder rapid communication during security events. Overall, Proton demonstrates strong data protection practices aligned with GDPR and Swiss privacy laws, supporting a resilient security culture.

Recommendations

  1. Enable DNSSEC on the proton.me domain to enhance DNS security and prevent spoofing.
  2. Publish a security.txt file at the root domain to facilitate responsible vulnerability disclosure.
  3. Provide explicit incident response contact information (e.g., security@proton.me) on the website.
  4. Maintain and publicize compliance certifications and security audit results to strengthen trust.
  5. Continue enhancing transparency around data retention policies and privacy compliance.

Contact details published on the site

Addresses
Legal name
Proton AG
Site observations

Automated reading of the public site. Ratings are indicative.

Business

Company
Proton AG
Description
Proton provides easy-to-use encrypted email, calendar, cloud storage, password manager, and VPN services, built on the principle of your data, your rules.
Key services
Proton Mail, Proton Calendar, Proton Drive, Proton Pass, Proton VPN, Proton Wallet, Proton Authenticator, Proton SimpleLogin, Lumo AI
Content quality
excellent
Branding
consistent

Technology

Stack
React, Astro, JavaScript, CSS, HTML
Frameworks
Astro, React
Platforms
Web, iOS, Android, Desktop (Windows, macOS, Linux)
Performance
fast
Mobile
excellent
Accessibility
good
SEO
excellent

Security

Observed score
90/100
Good practices seen
  • HTTPS enforced
  • End-to-end encryption
  • Zero-access encryption
  • Open source libraries
  • Independent security audits

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 rich content and no blocking.
  2. Strong emphasis on privacy, security, and Swiss jurisdiction.
  3. Comprehensive product ecosystem beyond email.
  4. Clear calls to action for free and business plans.
  5. Open source and audited security posture.
  6. No suspicious or malicious indicators found.
Technical notes

Notes

The website is built using modern web technologies including React and Astro, ensuring a fast, responsive, and accessible user experience across devices. The tech stack supports multiple platforms including web, desktop, and mobile apps. Hosting and domain registration are managed by reputable providers, with domain age supporting business maturity. SEO and metadata are well implemented, including comprehensive JSON-LD structured data and Open Graph tags. Performance is optimized with CDN usage for images and assets. Minor technical improvements include enabling DNSSEC and publishing security.txt for enhanced security posture.
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

Earlier scans of this domain

  1. 77/100Low26 findingsView report
  2. 77/100Low26 findingsView report
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