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Security report for postmarkapp.com

Postmark · Technology · United States

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

Security score

78/100

Risk levelLow

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

Postmark is a well-established email delivery service founded in 2009 and currently owned by ActiveCampaign, LLC. The company specializes in fast, reliable transactional and marketing email delivery targeted primarily at developers, startups, enterprises, and agencies. Their platform offers a comprehensive suite of services including Email API, SMTP service, message streams, email templates, inbound email, and analytics. The website reflects a mature business with a strong market position and a focus on deliverability and customer satisfaction. Technically, the site is built with modern JavaScript libraries and integrates multiple analytics and marketing tools, hosted likely on AWS infrastructure. The website is fast, mobile-optimized, and professionally designed with clear navigation and rich content. Security posture is strong with HTTPS enforced and domain registration protections in place, though DNSSEC is not enabled and some security headers are not explicitly detected. Privacy compliance is well addressed with clear privacy and cookie policies, though no explicit consent mechanism for cookies was detected. Contact information is primarily via web forms and physical address, with no direct emails or phone numbers publicly listed. Overall, the site is trustworthy, professional, and business-focused with no content safety concerns.

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

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 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 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 postmarkapp.com

This scan found 17 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
77
Security headers
50
Email security
85
DNS health
85
Network security
100
GDPR outside view
68
Average
78

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

Breach exposure

Leaked credentials and lookalike domains from OffSeq Breach. The counts are free; the detailed lists are paid add-ons.

Dark web exposure

Add-on

Leaked records that mention postmarkapp.com, from OffSeq Breach.

Total records
4,383
Employees
0
Customers
4,375
Third parties
8
Weak passwords
8%

9 subdomains affected

See the 10 newest leaked credentials

A one-off add-on to this report that lists the most recent identifier and password pairs OffSeq Breach holds for postmarkapp.com.

Select it in the checkout above.

Breach keeps ingesting new leaks, so these numbers can grow between scans.

Technical appendix

Business context, site observations and technical notes gathered during the scan, and the standards behind each reference.

Business context

Business profile

Postmark operates in the technology sector as a SaaS provider of email delivery services. Its business model revolves around subscription-based access to email APIs and SMTP services, targeting developers and businesses requiring reliable email infrastructure. The company benefits from its parent company ActiveCampaign's resources and brand recognition. Market positioning is strong with a focus on deliverability, ease of integration, and customer support. The presence of migration guides and comparisons to competitors like SendGrid and Mailgun indicates a competitive strategy to attract customers switching from other providers. The company maintains a positive customer satisfaction rating and leverages multiple marketing and analytics platforms to optimize growth and user engagement.

Security posture

Postmark demonstrates a mature security posture with HTTPS enforced and domain registration protections such as clientDeleteProhibited and clientTransferProhibited status flags. The absence of DNSSEC is a minor gap. The website does not expose sensitive data or vulnerable libraries in the HTML content. However, no explicit incident response or vulnerability disclosure information is publicly available, which could be improved. The use of multiple third-party analytics and marketing scripts increases the attack surface but is common for SaaS businesses. Overall, the security posture is strong but could benefit from enhanced transparency and additional DNS security measures.

Recommendations

  1. Enable DNSSEC on the domain to enhance DNS security and prevent spoofing.
  2. Publish a vulnerability disclosure policy or security.txt file to improve transparency and incident response readiness.
  3. Add or verify presence of security headers such as Content Security Policy (CSP), HTTP Strict Transport Security (HSTS), and X-Frame-Options.
  4. Consider implementing a cookie consent mechanism to comply with privacy regulations more explicitly.
  5. Provide direct security contact information or dedicated channels for incident reporting.

Contact details published on the site

Addresses
Legal name
ActiveCampaign, LLC
Site observations

Automated reading of the public site. Ratings are indicative.

Business

Company
Postmark
Description
Send transactional and marketing emails and get them to the inbox on time, every time. Postmark is a fast and reliable email delivery service for developers.
Key services
Email API, SMTP Service, Message Streams, Transactional Email, Email Delivery, Email Templates, Inbound Email, Analytics & Retention, Integrations
Content quality
excellent
Branding
consistent

Technology

Stack
JavaScript, Google Analytics, Microsoft Bing Ads, Facebook Pixel, Hotjar, Snowplow Analytics, Clarity, Amazon Ads, LinkedIn Insight Tag, Rewardful
Performance
fast
Mobile
excellent
Accessibility
good
SEO
good

Security

Observed score
85/100
Good practices seen
  • HTTPS enforced
  • Domain status includes clientDeleteProhibited, clientTransferProhibited, clientUpdateProhibited
  • No DNSSEC enabled (recommend enabling)
  • No exposed sensitive data in HTML
  • Use of secure API tokens in examples

Analytics and tracking

Services
Google Analytics, Microsoft Clarity, Snowplow Analytics, Hotjar
Tracking level
extensive
Privacy practices
good

Advertising

Ad networks
Amazon Ads, Bing Ads, Facebook Ads, Reddit Ads
Tracking pixels
Microsoft Clarity, Hotjar, Snowplow Analytics, Facebook Pixel, LinkedIn Insight Tag
Marketing tools
Clearbit
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 no blocking or WAF challenges.
  2. Strong focus on developer-friendly email delivery services.
  3. Comprehensive API and SMTP service offerings with multiple language libraries.
  4. Active use of modern analytics and marketing tools.
  5. Good customer satisfaction and trust signals.
  6. No exposed security vulnerabilities detected in the HTML content.
  7. No direct company contact emails or phone numbers found; contact primarily via forms and support pages.
  8. No explicit incident response or vulnerability disclosure information publicly available.
Technical notes

Notes

The website uses a modern tech stack with extensive use of JavaScript and integrates multiple analytics and marketing tools including Google Analytics, Microsoft Clarity, Hotjar, Snowplow, Facebook Pixel, and LinkedIn Insight Tag. Hosting is likely on AWS given the DNS servers. The site is fast, mobile-optimized, and well-structured with comprehensive meta tags and SEO optimizations. No CMS was detected, suggesting a custom or static site build. The technical implementation is robust with good performance and accessibility features. Opportunities exist to enhance security headers and DNS security. The site demonstrates low technical debt and good modernization, supporting reliable business operations.
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. 78/100 −1Low26 findingsView report
  2. 79/100Low21 findingsView report
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