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Security report for codesandbox.io

CodeSandbox · Technology · Iceland

Medium risk. 4 critical or high findings in Security headers and SSL/TLS.

Security score

70/100

Risk levelMedium

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

CodeSandbox is a cloud development platform founded in 2016 that enables developers to create, collaborate, and ship projects efficiently from any device. It holds a strong market position in the technology sector, targeting developers and teams seeking instant cloud development environments. The platform leverages modern web technologies including React and Next.js, hosted on Cloudflare infrastructure, ensuring fast performance and excellent mobile optimization. Security posture is solid with HTTPS enabled and domain transfer protections, though DNSSEC is not enabled and explicit security policies are not published. Privacy compliance is weak due to absence of visible privacy and cookie policies. Overall, the website is professional and trustworthy but could improve transparency and compliance documentation.

Scanned

NIS2 and GDPR posture

GDPR outside view
83/ 100 · Low
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 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. 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 codesandbox.io

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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
75
Security headers
15
Email security
65
DNS health
80
Network security
100
GDPR outside view
83
Average
70

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

CodeSandbox operates in the technology sector providing cloud-based development environments and collaboration tools. Its business model focuses on SaaS offerings for developers and teams. The domain age and WHOIS data align with the company's founding date, supporting legitimacy. The company uses privacy protection for domain registration, which is common in tech. The platform's ecosystem includes social media presence on Twitter but lacks visible partner or subsidiary domains. The website content is high quality and well-branded, supporting a medium-sized enterprise profile.

Security posture

The website employs HTTPS and Cloudflare DNS with clientTransferProhibited status, indicating good baseline security. However, DNSSEC is not enabled, which is a recommended best practice. No security headers or explicit security policies were found in the HTML content. There is no published vulnerability disclosure or security.txt file, limiting transparency for security researchers. No contact channels for incident response or abuse were identified. Overall, the security posture is moderate but could be enhanced by publishing security policies, enabling DNSSEC, and adding security headers.

Recommendations

  1. Enable DNSSEC to strengthen DNS security and prevent spoofing.
  2. Publish comprehensive privacy and cookie policies with GDPR compliance details.
  3. Add a security policy page and vulnerability disclosure or security.txt file.
  4. Implement and document security headers such as Content-Security-Policy and X-Frame-Options.
  5. Provide clear contact information including security and abuse contacts to improve trust.
Site observations

Automated reading of the public site. Ratings are indicative.

Business

Company
CodeSandbox
Description
CodeSandbox is a cloud development platform that empowers developers to code, collaborate and ship projects of any size from any device in record time.
Key services
cloud development environments, collaboration tools, project shipping
Content quality
excellent
Branding
consistent

Technology

Stack
React, Next.js, Cloudflare DNS, Web Fonts (woff2), Material Symbols Outlined
Frameworks
Next.js
Platforms
Cloud
Performance
fast
Mobile
excellent
Accessibility
good
SEO
good

Security

Observed score
75/100
Good practices seen
  • HTTPS enabled
  • clientTransferProhibited domain status

Analytics and tracking

Tracking level
minimal
Privacy practices
poor

Advertising

Transparency
poor

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
  2. No explicit privacy or cookie policies found in HTML content
  3. No visible contact emails or phone numbers on main page
  4. No security.txt or vulnerability disclosure found
  5. Modern tech stack with Next.js and React
  6. Domain uses Cloudflare DNS but DNSSEC not enabled
  7. WHOIS privacy protection used, common for tech companies
  8. No signs of adult or questionable content
  9. No advertising or tracking scripts explicitly detected in provided HTML
Technical notes

Notes

The website uses a modern tech stack with React and Next.js frameworks, optimized for performance and mobile responsiveness. Hosting is via Cloudflare, providing CDN and DNS services. The site uses web fonts and Material Symbols for UI consistency. SEO is supported by proper meta tags and Open Graph data. No CMS was detected, indicating a custom or framework-based site. Performance is fast with asynchronous script loading. Accessibility is good with focus-visible outlines and semantic HTML. Technical risks include lack of DNSSEC and missing security headers, which should be addressed to reduce attack surface.
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. 70/100Medium31 findingsView report
  2. 70/100Medium31 findingsView report
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