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Security report for webcontainers.io

StackBlitz, Inc. · Technology · United Kingdom

Medium risk. 7 critical or high findings in Email security, Security headers and 2 other checks.

Security score

61/100

Risk levelMedium

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

WebContainers.io is a technology-focused website operated by StackBlitz, Inc., offering an innovative API that enables running Node.js environments directly in web browsers. The platform targets developers, educational platforms, and enterprises seeking to embed interactive, production-ready development environments into their web applications. The website demonstrates a strong market position with endorsements from major technology companies and a clear focus on developer experience and modern web technologies. Technically, the site leverages modern JavaScript frameworks such as Vue.js and VitePress, integrates WebAssembly, and uses Algolia for search and Google Analytics for user insights. The site is performant, mobile-optimized, and accessible, reflecting a mature digital infrastructure. Security-wise, the site enforces HTTPS, uses domain transfer protection, and anonymizes IPs in analytics, though it lacks DNSSEC and explicit security policies or vulnerability disclosure mechanisms. Privacy compliance is partially met with a clear privacy policy but lacks cookie consent mechanisms. Overall, the website is professional, trustworthy, and well-positioned in its niche, with room for improvement in security transparency and privacy controls.

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. Email security

    SPF, DKIM and DMARC stop others sending email that looks like it comes from your domain, a common route to phishing and invoice fraud.

    • Critical

      No email authentication configured

      Domain is vulnerable to email spoofing

      What to do: Implement SPF, DKIM, and DMARC immediately

  2. 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';…

  3. 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 webcontainers.io

This scan found 27 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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  • 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
52
Security headers
30
Email security
60
DNS health
70
Network security
100
GDPR outside view
53
Average
61

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

StackBlitz, Inc. operates WebContainers.io as part of its broader developer tooling ecosystem. The business model centers on providing SaaS APIs that enable browser-based Node.js runtimes, facilitating interactive tutorials, IDEs, and embedded development environments. The company targets a diverse audience including startups, open source maintainers, and large enterprises, supported by a medium-sized team founded in 2019. The website highlights partnerships and usage by industry leaders such as Google, Shopify, and Cloudflare, indicating strong market validation. Revenue streams likely include API subscriptions and enterprise licensing. The company maintains active community engagement via GitHub, Twitter, and Discord, fostering a robust ecosystem. Strategic observations include leveraging modern web technologies to reduce server costs and accelerate product shipping, positioning StackBlitz as a competitive innovator in cloud-based developer tools.

Security posture

The security posture of WebContainers.io is solid with mandatory HTTPS, domain transfer lock, and anonymized analytics data. However, the absence of DNSSEC reduces DNS security resilience. No explicit security policies, incident response contacts, or vulnerability disclosure mechanisms are published, which could hinder rapid response to security incidents. The site does not implement a cookie consent mechanism, which may affect GDPR compliance. No vulnerabilities or exposed sensitive data were detected in the HTML content. Overall, the site demonstrates good security hygiene but would benefit from enhanced transparency and formalized security processes to improve trust and compliance.

Recommendations

  1. Enable DNSSEC on the domain to enhance DNS security and prevent spoofing.
  2. Publish a dedicated security policy and incident response contact information to improve transparency and readiness.
  3. Implement a cookie consent banner or mechanism to comply fully with GDPR and other privacy regulations.
  4. Add a security.txt file to facilitate responsible vulnerability disclosure and improve security posture.
  5. Regularly audit and document HTTP security headers and ensure best practices are consistently applied.
Site observations

Automated reading of the public site. Ratings are indicative.

Business

Company
StackBlitz, Inc.
Description
Build the future of web based coding experiences, from interactive tutorials to instant production-ready dev environments.
Key services
WebContainer API for running Node.js in browser, Interactive tutorials and coding environments, Integration of full-stack dev environments into web apps
Content quality
excellent
Branding
consistent

Technology

Stack
JavaScript, TypeScript, Vue.js (VitePress), WebAssembly, Algolia Search, Google Analytics
Frameworks
VitePress, Vue.js
Performance
fast
Mobile
excellent
Accessibility
good
SEO
good

Security

Observed score
85/100
Good practices seen
  • HTTPS enforced
  • ClientTransferProhibited domain status
  • No exposed sensitive data in HTML
  • Use of anonymize_ip in Google Analytics

Analytics and tracking

Services
Google Analytics
Tracking level
moderate
Privacy practices
basic

Advertising

Marketing tools
Algolia Search
Transparency
basic

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 mechanisms.
  2. Strong branding and consistent messaging focused on WebContainer API technology.
  3. Multiple reputable client testimonials and partner logos enhance trust.
  4. No direct contact emails or phone numbers found on the main site; contact likely via StackBlitz main site.
  5. No explicit cookie consent mechanism detected despite GDPR relevant policies.
  6. Use of modern web technologies and frameworks ensures good performance and UX.
  7. Security posture is good but could be improved with DNSSEC and explicit security policies.
Technical notes

Notes

The website is built using modern web technologies including Vue.js and VitePress, ensuring a fast, responsive, and accessible user experience. Integration with Algolia provides efficient search capabilities, while Google Tag Manager and Analytics enable user behavior tracking with IP anonymization. The site is mobile-optimized and features a clean, professional design with clear navigation. Hosting details are not explicit but the domain registrar is reputable. Performance is fast with preloading of critical assets and module preloading for JavaScript chunks. No CMS was detected, indicating a custom or static site generation approach. Technical risks are minimal but could include reliance on third-party analytics and absence of DNSSEC. Overall, the technical infrastructure supports the business goals effectively with opportunities for incremental security enhancements.
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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