What does StackOptic analyze?

StackOptic runs 18 analysis modules on any public website from a single URL. It detects 7,000+ technologies (CMS, frameworks, analytics, payments, CDN, hosting), evaluates SSL certificates and HTTP security headers with grades from A+ to F, measures Core Web Vitals (LCP, CLS, TBT, FCP), audits SEO meta tags and structured data, checks email security (SPF, DKIM, DMARC), analyzes AI & LLM readiness including bot access and llms.txt validation, extracts color palettes and typography, estimates carbon footprint, and generates permanent shareable reports.

Does it work on sites behind Cloudflare or bot protection?

Yes. StackOptic uses a real browser engine that loads pages exactly like a human visitor — executing JavaScript, rendering CSS, and handling redirects. This allows it to bypass Cloudflare, LiteSpeed, Sucuri, and other bot protection systems where traditional crawlers and HTTP-only tools fail.

What do I get on the free plan?

The free plan includes 5 analyses per day with access to all 18 modules, full scores, technology detection, and security grades. Every report is permanently accessible via a unique shareable URL — no login required to view. No credit card needed. AI-powered insights, re-analysis, PDF/JSON export, and comparison features are available on Pro ($24/mo) and Agency ($99/mo) plans.

What is AI & LLM readiness analysis?

This module evaluates how visible and citable your website is to AI search engines like ChatGPT, Perplexity, Google AI Overviews, and Claude. It audits access permissions for 8 major AI bots, validates llms.txt and llms-full.txt files, scores citation-ready content structure, and analyzes structured data (JSON-LD) for GEO readiness — helping you rank in the next generation of search.

How long does an analysis take?

Most analyses complete in under 10 seconds. StackOptic runs all 18 modules in parallel using a real browser session, so you get technology detection, security audit, performance metrics, SEO analysis, and AI readiness scoring simultaneously.

How accurate are the results?

Detection is based on real browser execution — DOM inspection, JavaScript runtime analysis, HTTP headers, and DNS records. With 7,000+ technology signatures and Lighthouse-calibrated performance scoring, StackOptic achieves high accuracy for mainstream technologies.

What security checks are performed?

The security module evaluates SSL/TLS certificates, 12+ HTTP security headers (HSTS, CSP, X-Frame-Options, Permissions-Policy, Referrer-Policy), HTTPS enforcement, and email authentication (SPF, DKIM, DMARC). Each site receives a letter grade from A+ to F with specific remediation steps.

Do you store the websites I analyze?

StackOptic only stores publicly available information that any visitor to a website would see — HTML content, HTTP headers, DNS records, and screenshots. We do not access private data, log in to websites, or perform any intrusive testing.

Back to Search

zum.de

https://zum.de· First analyzed 19 Feb 2026· Updated 19 Feb 2026

Export

zum.de

Sponsored

Hosting Provider

Hetzner

hetzner.com

IP Address

46.4.65.203

Server Location

🇩🇪 Falkenstein, Germany

ASN

AS24940

Organization

Hetzner

Server

Nginx

Nameservers

robotns3.second-ns.com.ns1.first-ns.de.robotns2.second-ns.de.

Performance

Page Speed

1.4 MB

63 requests

Image Optimization

Lazy LoadResponsive

0–49

50–89

90–100

Architecture Stack

Monolithic

⚙️ SSR

WordPressv6.9.1

cms

isoneCustom

Technology Stack

10 Technologies Detected

Plugins

To Top Wp User Avatar Complianz Gdpr Wp Ajax Pagination

Libraries

CSS Frameworks

Icon Libraries

Analytics

Email Marketing

Web Servers

SEO Analysis

D44/100

zum.dezum.de

Zentrale für Unterrichtsmedien im Internet e.V.

No description available for this page.

Title Length47 chars

Recommended: 50-60 chars

Description Length0 chars

Recommended: 120-160 chars

Issues (3)

• Missing meta description - important for click-through rates
• Missing H1 tag - every page should have one H1
• Many images missing alt text (23/29)

6 issues found

Upgrade to view details

Crawlability

Sitemap

robots.txt

3 rules

Sponsored

Security Score

26%Critical

Interactive

HTTPS

No WAF

53d

Certificate Details

Type

Domain Validated (DV)

Certificate Authority

Let's Encrypt

Key Algorithm

RSA (2048 bit)

Signature

SHA-256 with RSA

TLS Version

TLSv1.2

HTTP Protocol

HTTP/1.1

Valid From

14.01.2026

Valid Until

14.04.2026

Subject Alternative Names (2)

www.zum.dezum.de

SHA-256 Fingerprint

DB:81:CC:FE:1B:8E:73:3D:65:BC:40:0E:A2:A0:A4:AD:26:B1:8B:04...

Top Recommendations

Security recommendation preview

Upgrade to view recommendations

Upgrade to view header details

HTTP Headers

Developer Console

connection

Keep-Alive

content-encoding

📦 Gzip(gzip)

content-language

content-type

text/html; charset=UTF-8

date

Thu, 19 Feb 2026 14:15:09 GMT

keep-alive

timeout=5, max=99

Good Warning Issue

Email Infrastructure

Custom Mail Server

Score

SPF

DKIM

DMARC

DMARC Policy

None (Monitor Only)

MX Records (1)

zumserver.zum.de

Domain Information

zum.de

Last Updated

06.05.2014

DNSSEC

Not Enabled

Privacy & Compliance

Complianz

Cookie Consent Banner

Complianz

GDPR Indicators

Cookie consent banner detected

CMP: Complianz

Typography & Readability

Open Sans Light + Open Sans

49/100

Readability

/30

40/40

16px · LH 1.50

Hierarchy

/20

8/25

WCAG

/25

5/15

Contrast: undefined

Performance

/25

13/20

2 fonts

Heading Font

Open Sans Light

Sans

Body Font

Open Sans

Sans16px

Contrast Ratio

Reading Comfort

~40 CPL

Needs attention

24px

28px

16px

Minor Third

Scale

✅ Excellent readability: 16px body text is ideal for all devices.

✅ Optimal line spacing: 1.50 ratio ensures comfortable reading.

✅ Good performance: Using 2 font families keeps load times fast.

⚠️ Risky: Text appears on background images without overlay protection.

⚠️ Cramped layout: 8 elements lack adequate spacing.

Buy on MyFonts

Business & Marketing Stack

3 Tools Detected

Advanced

Behavior Analytics

Matomo (Piwik)Mid-Market

Google AnalyticsFree

User behavior and product analytics

Privacy & Cookies

ComplianzSMB

Cookie consent and privacy compliance tools

Sponsored

Scripts & Styles

25 Resources

Scripts

Styles

Async

Defer

Top Script Sources

zum.de(11)lehreronline.adspirit.de(2)cdn.adspirit.de(2)stats.zum.de(1)

Website Identity

zum.de

Social Profiles

Instagram Bluesky

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Last analyzed: 19 Feb 2026 at 14:15

Historical Analysis & Change Tracking