Skip to main content

Security report for hackmd.io

HackMD · Technology · Taiwan

Low risk. 2 critical or high findings in Security headers and GDPR outside view.

Security score

82/100

Risk levelLow

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

HackMD is a collaborative Markdown editor platform founded in 2015 and based in Taiwan. It offers real-time document editing and sharing capabilities targeted at teams, developers, researchers, educators, and communities. The platform supports integrations such as GitHub and provides features like templates, book mode, and UML graph visualization, positioning itself as a versatile tool for knowledge sharing and collaboration. The business model is primarily freemium SaaS with paid tiers for teams and enterprises, serving a global user base including notable organizations like the Ethereum Foundation. Technically, HackMD employs modern web technologies including React and Next.js, hosted on AWS infrastructure. The website demonstrates excellent performance, mobile optimization, and SEO practices. Security is robust with HTTPS enforcement, CSRF protections, and domain transfer restrictions, although DNSSEC is not enabled. Privacy and terms policies are comprehensive and GDPR compliant, with active use of analytics tools such as Google Tag Manager and Plausible Analytics. Security posture is strong with no detected vulnerabilities or exposed sensitive data. However, explicit incident response contacts and vulnerability disclosure mechanisms are not publicly evident, representing an area for improvement. The WHOIS data is transparent and consistent with the business identity, supporting legitimacy and trustworthiness. Overall, HackMD presents a professional, secure, and user-friendly platform with a strong market position in collaborative documentation tools. Strategic recommendations include enabling DNSSEC, publishing explicit security headers, and establishing clear incident response and vulnerability disclosure channels to further enhance security and trust.

Scanned

NIS2 and GDPR posture

GDPR outside view
68/ 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

2 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 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

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

Keep watching hackmd.io

This scan found 15 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

Email alerts on material changes and an exportable JSON history of every change.

Billed monthly to your card. Cancel anytime. The full timeline opens with your unlock code.

Full report

€39.90one-time

  • The complete analysis as a PDF you can cite
  • Email delivery with an unlock code
  • Lifetime access to this report

Prices incl. 21% VAT. Secure checkout by Mollie; sold by SEQ SIA, Latvia.

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
100
Security headers
60
Email security
80
DNS health
85
Network security
100
GDPR outside view
68
Average
82

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

HackMD occupies a competitive niche in the collaborative documentation and Markdown editor market, leveraging real-time editing and integrations to attract a diverse audience from startups to established institutions. Its freemium SaaS model allows broad adoption with monetization through team and enterprise plans. The company benefits from strong community engagement and endorsements from reputable organizations, enhancing its market credibility. The partnership ecosystem includes social media channels and community platforms like Discord. Growth indicators include a large user base (1 million users, 30k teams) and global reach (170 countries). The company maintains consistent branding and professional content, supporting sustained market presence.

Security posture

The website demonstrates a mature security posture with HTTPS enforced, clientTransferProhibited domain status, and CSRF tokens in forms. No critical vulnerabilities or exposed sensitive data were detected in the HTML content. Privacy policies and cookie consent mechanisms are in place, indicating compliance with GDPR. However, the absence of explicit incident response contact information and a security.txt file suggests room for improvement in vulnerability management and incident handling transparency. DNSSEC is not enabled, which could be a potential DNS security enhancement. Overall, the security culture appears proactive but could benefit from formalized disclosure and response processes.

Recommendations

  1. Enable DNSSEC on the domain to enhance DNS security and prevent spoofing.
  2. Publish explicit security headers such as Content-Security-Policy and X-Frame-Options to mitigate common web attacks.
  3. Establish and publicize a dedicated incident response contact or security email address to improve vulnerability reporting and response.
  4. Create and maintain a security.txt file to facilitate responsible vulnerability disclosure.
  5. Continue to monitor and update third-party libraries and dependencies to avoid potential vulnerabilities.
Site observations

Automated reading of the public site. Ratings are indicative.

Business

Company
HackMD
Description
HackMD provides a real-time collaborative Markdown editor for teams and individuals to create, share, and edit documents seamlessly.
Key services
Real-time Markdown editing, Document collaboration, GitHub integration, Templates and book mode, UML graph visualization
Content quality
excellent
Branding
consistent

Technology

Stack
React, Next.js, JavaScript, WebAssembly (possible for UML rendering), AWS DNS hosting
Frameworks
Next.js
Platforms
Web
Performance
fast
Mobile
excellent
Accessibility
good
SEO
good

Security

Observed score
85/100
Good practices seen
  • HTTPS enforced
  • ClientTransferProhibited domain status
  • CSRF tokens in forms
  • No exposed sensitive data in HTML

Analytics and tracking

Services
Google Tag Manager, Plausible Analytics
Tracking level
moderate
Privacy practices
good

Advertising

Tracking pixels
Plausible Analytics
Marketing tools
Plausible Analytics
Transparency
good

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 presence of privacy and terms policies with clear URLs.
  3. Multiple social media channels linked and active.
  4. Modern web technologies and frameworks used.
  5. Good security posture with HTTPS and CSRF protections.
  6. No explicit incident response or vulnerability disclosure page found.
  7. WHOIS data is transparent and consistent with business identity.
  8. No suspicious or malicious indicators detected.
Technical notes

Notes

HackMD's technical infrastructure is modern and robust, utilizing React and Next.js frameworks for a performant and responsive web experience. Hosting on AWS DNS services provides reliable availability. The website is optimized for mobile devices and accessibility, with comprehensive meta tags supporting SEO. The use of CSRF tokens in forms indicates attention to secure data handling. Analytics integration is balanced with privacy compliance. No CMS was detected, suggesting a custom-built platform. Performance is fast with efficient resource loading and preloading strategies. Technical risks are minimal but could be further mitigated by enabling DNSSEC and enhancing security headers.
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

Reviews of this site

Share your experience with hackmd.io. Every review is verified by email and published after moderation.

Overall rating
Select a rating
4000 characters remaining

We’ll email you to confirm your review and keep your details private.

Community rating

No published reviews yet. Be the first to review hackmd.io.

Feedback on this report

Rate this report, add an optional comment, and tell us if you want a security specialist to follow up.

Overall report quality
Select a rating
2000 characters remaining

We only use your feedback to improve Guard reports. Contact details are never shared.