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Security report for sankeymatic.com

SankeyMATIC · Technology · N/a

High risk. 7 critical or high findings in Security headers, GDPR outside view and 2 other checks.

Security score

47/100

Risk levelHigh

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

SankeyMATIC is a niche online tool focused on enabling users to create Sankey diagrams easily and visually. It targets a broad audience including analysts, educators, and anyone interested in visualizing flow data such as budgets, elections, or financial results. The website is small-scale, independently produced by Steve Bogart, and offers free access without requiring user registration. The business model relies on voluntary contributions and advertising revenue via Google AdSense. Technically, the site uses standard web technologies including HTML5, CSS3, JavaScript, and the D3.js library for rendering diagrams. Hosting is provided by pair Networks, Inc. The site is moderately optimized for performance and mobile use, with good SEO practices and basic accessibility features. The source code is openly available on GitHub, enhancing transparency and trust. From a security perspective, the site uses HTTPS but lacks advanced security headers and DNSSEC is not enabled, which could be improved. No forms or user data collection mechanisms are present, reducing attack surface. Privacy compliance is basic with a privacy policy present but no cookie consent or GDPR-specific statements. No incident response or vulnerability disclosure policies are published. Overall, SankeyMATIC presents a trustworthy and professional web presence with a clear focus on its specialized service. Security and privacy practices could be enhanced to align with modern standards, and adding contact information and terms of service would improve business credibility and compliance.

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

7 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 Strict-Transport-Security header

      Forces HTTPS connections

      What to do: Add "Strict-Transport-Security: max-age=31536000; includeSubDomains; preload"

      • CWE-319
      • OWASP A04:2025
      • ASVS V3.4.1
    • 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

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

Keep watching sankeymatic.com

This scan found 29 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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Recommended

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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
62
Security headers
15
Email security
70
DNS health
60
Network security
20
GDPR outside view
53
Average
47

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

SankeyMATIC occupies a specialized niche in the data visualization market, offering a free, easy-to-use Sankey diagram builder. Its competitive advantage lies in simplicity, no registration requirement, and open source roots. Revenue is generated primarily through advertising and voluntary support. The target customers are data analysts, educators, and general users needing flow diagrams. The site shows steady maturity with a domain age since 2013 and consistent content updates. Partnerships are limited but include the personal site of the developer. The business operates independently without subsidiaries or parent companies.

Security posture

The website demonstrates a basic security posture with HTTPS enabled but lacks implementation of important security headers such as Content-Security-Policy and Strict-Transport-Security. DNSSEC is not enabled, which is a missed opportunity to secure DNS resolution. No forms or user input reduce risk exposure. Privacy policy exists but lacks GDPR compliance details and no cookie consent mechanism is present. No published incident response or vulnerability disclosure policies limit transparency in security management. Overall, the site is low risk but could improve security maturity to better protect users and data.

Recommendations

  1. Enable DNSSEC on the domain to enhance DNS security and prevent spoofing.
  2. Implement key HTTP security headers including Content-Security-Policy, X-Frame-Options, and Strict-Transport-Security.
  3. Add a cookie consent banner or mechanism to comply with privacy regulations such as GDPR.
  4. Publish a clear security policy and incident response contact information to improve transparency and trust.
  5. Provide contact information and terms of service to enhance business credibility and user confidence.
Site observations

Automated reading of the public site. Ratings are indicative.

Business

Company
SankeyMATIC
Description
An online Sankey diagram builder for everyone that allows users to create flow diagrams to visualize budgets, financial results, application processes, elections, and more.
Key services
Online Sankey diagram builder, Diagram customization, Export diagrams as PNG or SVG, Save and resume work with plain text files
Content quality
good
Branding
consistent

Technology

Stack
HTML5, CSS3, JavaScript, D3.js, Google AdSense
Performance
moderate
Mobile
good
Accessibility
basic
SEO
good

Security

Observed score
65/100
Good practices seen
  • HTTPS enabled

Analytics and tracking

Tracking level
minimal
Privacy practices
basic

Advertising

Ad networks
Google AdSense
Transparency
basic

Site quality

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

Key observations

  1. Website provides a specialized free tool for Sankey diagram creation.
  2. No contact emails or phone numbers explicitly provided on the site.
  3. No cookie consent mechanism or terms of service found.
  4. Privacy policy is present but basic and lacks explicit GDPR compliance statements.
  5. Use of Google AdSense for monetization with ads embedded.
  6. No forms detected that collect user data.
  7. No security.txt or vulnerability disclosure policy found.
  8. Site uses HTTPS but lacks advanced security headers.
  9. No social media links except Mastodon accounts.
  10. Source code is openly available on GitHub, indicating transparency.
Technical notes

Notes

The website is built on a solid technical foundation using modern web standards and the D3.js visualization library. Hosting is stable with pair Networks, Inc. Performance is moderate with room for optimization. The site is mobile responsive and SEO optimized with proper meta tags. No CMS detected, indicating a custom or static site approach. Use of Google AdSense introduces third-party scripts but no analytics services were detected. The site lacks advanced accessibility features but meets basic standards. Technical debt appears low with clean HTML and CSS. Opportunities exist to improve security headers and implement 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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