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.

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zdf.de

https://zdf.de· First analyzed 11 Feb 2026· Updated 11 Feb 2026

Export

zdf.de

Mobile

Sponsored

Hosting Provider

ZDF Zweites Deutsches Fernsehen

IP Address

91.197.29.78

Server Location

🇩🇪 Mainz, Germany

ASN

AS43354

Organization

ZDF Zweites Deutsches Fernsehen

Nameservers

a14-66.akam.net.a10-64.akam.net.a22-67.akam.net.a11-65.akam.net.+4 more

Performance

Page Speed

8.3 MB

250 requests

Image Optimization

Lazy LoadResponsive

0–49

50–89

90–100

Architecture Stack

Hybrid

🔀 Hybrid

Frontend

Framework

Next.js

Infrastructure

Hosting

ZDF Zweites Deutsches Fernsehen

Progressive Web App

Web ManifestApple Touch IconTheme Color

Technology Stack

4 Technologies Detected

Meta Frameworks

Next.js Astro

Frameworks

Angular

Other

D3.js

SEO Analysis

A82/100

zdf.dezdf.de

ZDF Streaming-Portal: Filme, Serien und Dokus online anschauen

Alle Videos und Livestreams im ZDF anschauen - ständig verfügbar und interaktiv! Entdecke Filme, Serien, Sportevents, Dokumentationen und vieles mehr!

Title Length62 chars

Recommended: 50-60 chars

Description Length150 chars

Recommended: 120-160 chars

Issues (1)

• Many images missing alt text (688/700)

2 issues found

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Sponsored

Security Score

81%Very Good

Static / Informational

HTTPS

No WAF

182d

Certificate Details

Type

Organization Validated (OV)

Certificate Authority

DigiCert Inc

Key Algorithm

RSA (2048 bit)

Signature

SHA-256 with RSA

TLS Version

TLSv1.3

HTTP Protocol

HTTP/2

Valid From

13.08.2025

Valid Until

12.08.2026

OCSP Stapling

Enabled

Subject Alternative Names (20)

www.zdf.de*.3sat.de*.heute.de*.logo.de*.phoenix.de*.sc.zdf.de*.tivi.de*.zdf.de+12 more

SHA-256 Fingerprint

7B:25:0E:76:55:1D:1A:28:B7:59:1F:35:E1:45:5B:A1:12:7D:8C:2A...

Recommendations

Security recommendation preview

Upgrade to view recommendations

Upgrade to view header details

HTTP Headers

Developer Console

accept-ranges

bytes

cache-control

🟡 3s(public, max-age=3)

cache-status

ingress-cache; hit; ttl=28.657; detail='now:Wed, 11 Feb 2026...

content-encoding

📦 Gzip(gzip)

content-length

586690

content-type

text/html; charset=utf-8

Good Warning Issue

Email Infrastructure

Custom Mail Server

Score

100

SPF

DKIM

DMARC

DMARC Policy

Reject (Strictest)

MX Records (1)

mail.zdf.de

Privacy & Compliance

Cookie Consent Banner

GDPR Indicators

Typography & Readability

nextGeneratedFontDeclarationsZDFTypeCond + nextGeneratedFontDeclarationsZDFMicro

72/100

Readability

/30

24/40

14px · LH 1.30

Hierarchy

/20

25/25

2.29x ratio

WCAG

/25

15/15

Contrast: undefined

Performance

/25

13/20

2 fonts

Heading Font

nextGeneratedFontDeclarationsZDFTypeCond

Sans32px

Body Font

nextGeneratedFontDeclarationsZDFMicro

Sans14px

Contrast Ratio

Reading Comfort

~41 CPL

Needs attention

32px

14px

Minor Second

Scale

⚠️ Small text: 14px may be hard to read on mobile. Consider 16px+.

✅ Strong hierarchy: Headlines are 2.3x larger than body text.

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

✅ Smart font loading: Using font-display: swap prevents invisible text during load.

✅ Protected text on images: Using gradient for readability.

⚠️ Cramped layout: 452 elements lack adequate spacing.

Buy on MyFonts

Business & Marketing Stack

1 Tools Detected

Growing

Behavior Analytics

Google AnalyticsFree

User behavior and product analytics

Sponsored

Scripts & Styles

30 Resources

Scripts

Styles

Async

Defer

Top Script Sources

local(20)

Website Identity

Facebook Instagram TikTok

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Last analyzed: 11 Feb 2026 at 12:26

Historical Analysis & Change Tracking