Skip to main content

Security report for postmarkapp.com

Postmark · Technology · US

Low risk. 3 critical or high findings in Security headers and GDPR outside view.

Security score

79/100

Risk levelLow

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

Postmark is a technology company specializing in fast and reliable email delivery services tailored for developers and businesses of various sizes. Positioned as a trusted provider since 2010, Postmark offers a comprehensive suite of email-related services including API and SMTP services, message streams, transactional email, and analytics. The company targets developers, startups, enterprises, and agencies, leveraging its strong market position and parent company ActiveCampaign's backing. The website reflects a mature business model focused on SaaS delivery with a strong emphasis on deliverability and customer satisfaction. Technically, Postmark employs a robust infrastructure hosted on Amazon AWS, using nginx and Kong API gateway, with a valid Amazon-issued SSL certificate. The site demonstrates good performance, mobile optimization, and SEO practices, supported by comprehensive content and clear navigation. Security-wise, the site implements essential HTTP security headers and uses a valid SSL certificate but lacks advanced features like HSTS and DNSSEC. No public incident response or vulnerability disclosure mechanisms were found, indicating room for improvement in transparency and security communication. Overall, Postmark presents a professional, trustworthy, and technically sound online presence with a focus on developer usability and customer support.

Scanned

This is an earlier scan of postmarkapp.com. View the latest report

NIS2 and GDPR posture

GDPR outside view
58/ 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

3 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

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

Keep watching postmarkapp.com

This scan found 14 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. See sample alerts.

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
85
Security headers
50
Email security
95
DNS health
85
Network security
100
GDPR outside view
58
Average
79

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, providing email delivery services primarily to developers and businesses requiring reliable transactional and marketing email solutions. Its competitive advantages include a strong focus on deliverability, ease of integration via multiple official libraries, and a customer-centric approach evidenced by high customer happiness ratings and extensive testimonials. The business model is subscription-based SaaS, with revenue streams likely from tiered pricing plans and additional services like dedicated IPs and referral programs. The target customer segments range from startups and bootstrapped companies to enterprises and agencies. The company benefits from its parent company ActiveCampaign, which expands its ecosystem and market reach. Strategic partnerships and integrations enhance its service offerings. The website content and structure indicate a mature marketing strategy with clear calls to action and educational resources, supporting customer acquisition and retention.

Security posture

Postmark demonstrates a solid security posture with implementation of key HTTP security headers such as X-Frame-Options, X-XSS-Protection, and X-Content-Type-Options, alongside a valid SSL certificate issued by Amazon. The absence of deprecated SSL/TLS protocols and known vulnerabilities like Heartbleed or POODLE is positive. However, the lack of HSTS, DNSSEC, and CAA records suggests opportunities to strengthen domain and transport layer security. No explicit incident response or vulnerability disclosure pages were found, which could impact transparency and trust in security incident handling. GDPR compliance is indicated by the presence of privacy and cookie policies, but no explicit data protection officer contact or security framework certifications were identified. Overall, the security maturity is good but could be enhanced by adopting additional best practices and public security communication.

Recommendations

  1. Enable HTTP Strict Transport Security (HSTS) with includeSubDomains and preload to enforce HTTPS and prevent downgrade attacks.
  2. Implement DNSSEC to protect DNS integrity and prevent spoofing or cache poisoning attacks.
  3. Add Certification Authority Authorization (CAA) DNS records to restrict which CAs can issue certificates for the domain.
  4. Publish a security.txt file to provide clear vulnerability disclosure and security contact information.
  5. Develop and publicly share incident response and security policies to improve transparency and customer trust.

Contact details published on the site

Addresses
Legal name
ActiveCampaign, LLC
Technical notes

Notes

The website is hosted on Amazon AWS infrastructure, utilizing nginx as the web server and Kong as an API gateway, indicating a modern and scalable architecture. The SSL certificate is Amazon RSA 2048-bit, valid and not self-signed, but the site does not support TLS 1.2 or TLS 1.3, which is unusual and may require review. The tech stack includes multiple official Postmark libraries for various programming languages, enhancing developer integration. Performance metrics indicate fast load times, though no explicit resource counts or page sizes were provided. The site uses custom or unknown CMS, with well-structured HTML and JSON-LD structured data for SEO and business information. Mobile optimization and accessibility are good, with clear navigation and consistent branding. Technical risks include missing advanced security configurations and potential SSL/TLS protocol support issues that could affect compatibility and security.
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. 78/100Low26 findingsView report
  2. 78/100Low26 findingsView report
Reviews of this site

Share your experience with postmarkapp.com. 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 postmarkapp.com.

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.