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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centrum.cz

https://centrum.cz· First analyzed 19 Feb 2026· Updated 19 Feb 2026

Export

centrum.cz

Sponsored

Hosting Provider

Economia Infrastructure

IP Address

46.255.231.129

Server Location

🇨🇿 Prague, Czechia

ASN

AS43614

Organization

Economia Infrastructure

Server

Cloudflare

CDN

Cloudflare

WAF

Cloudflare

Nameservers

pam.ns.cloudflare.com.max.ns.cloudflare.com.

Performance

Page Speed

465 KB

250 requests

Image Optimization

Lazy LoadWebPResponsive

0–49

50–89

90–100

Architecture Stack

Hybrid

🔀 Hybrid

Frontend

Framework

Next.js

Styling

Tailwind CSS

CMS

WordPress

Infrastructure

Hosting

Economia Infrastructure

CDN

Cloudflare

Technology Stack

12 Technologies Detected

Analytics

Google Analytics

Google Analytics 4

Facebook Pixel

Advertising

Google Ads Google AdSense Criteo

Meta Frameworks

CSS Frameworks

Tag Managers

CDN

SEO Analysis

C64/100

centrum.czcentrum.cz

Centrum.cz: Fandíme dobrému obsahu

Centrum.cz je český internetový portál nabízející e-mail, aktuální zpravodajství, počasí a další zajímavé služby.

Title Length34 chars

Recommended: 50-60 chars

Description Length113 chars

Recommended: 120-160 chars

Issues (1)

• Missing H1 tag - every page should have one H1

5 issues found

Upgrade to view details

Crawlability

Sitemap

robots.txt

2 rules

Sitemap reference found

Allows all crawlers

Sponsored

Security Score

26%Critical

Interactive

HTTPS

WAF

87d

Certificate Details

Type

Domain Validated (DV)

Certificate Authority

Google Trust Services

Key Algorithm

ECDSA (secp256r1) (256 bit)

Signature

ECDSA with SHA-256

TLS Version

TLSv1.3

HTTP Protocol

HTTP/2

Valid From

17.02.2026

Valid Until

18.05.2026

OCSP Stapling

Enabled

Subject Alternative Names (2)

centrum.cz*.centrum.cz

SHA-256 Fingerprint

3D:DC:DA:22:FF:7E:99:85:E4:F8:C0:F6:7C:0F:4B:F2:7F:89:AC:33...

Top Recommendations

Security recommendation preview

Upgrade to view recommendations

Upgrade to view header details

HTTP Headers

Developer Console

age

cache-control

🟡 180s(public, max-age=180)

cf-cache-status

HIT

cf-ray🇩🇪 Frankfurt

9d07fe5ddcc6803d-FRA

content-encoding

⚡ Brotli(br)

content-type

text/html; charset=utf-8

Good Warning Issue

Email Infrastructure

Custom Mail Server

Score

SPF

DKIM

DMARC

DMARC Policy

None (Monitor Only)

MX Records (4)

centrum-cz-20mx2.eco-mx.cz

centrum-cz-20mx1.eco-mx.cz

centrum-cz-10mx1.eco-mx.cz

centrum-cz-10mx2.eco-mx.cz

Domain Information

centrum.cz

Domain Age

28y 7m

Created

12.07.1997

Expires

23.10.2026

Last Updated

19.06.2019

Registrar

REG-WEBGLOBE

DNSSEC

Not Enabled

Privacy & Compliance

Cookiebot

Cookie Consent Banner

Cookiebot

GDPR Indicators

Cookie consent banner detected

CMP: Cookiebot

Data Protection Officer mentioned

Typography & Readability

Arial

50/100

Readability

/30

12/40

12px · LH 1.30

Hierarchy

/20

8/25

WCAG

/25

15/15

Contrast: undefined

Performance

/25

20/20

System fonts

Heading Font

Arial

Sans

Body Font

Arial

Sans12px

Contrast Ratio

Reading Comfort

~44 CPL

Needs attention

12px

16px

12px

Perfect Fourth

Scale

❌ Critical: 12px body text is too small. Increase to at least 14px.

✅ Excellent performance: System fonts eliminate font loading delays (better LCP).

✅ Consistent design: Single font family with weight variations is a modern best practice.

⚠️ Cramped layout: 30 elements lack adequate spacing.

✅ Clean layout: Consistent left alignment throughout.

Business & Marketing Stack

7 Tools Detected

Enterprise

Behavior Analytics

Google Tag ManagerFree

Google AnalyticsFree

User behavior and product analytics

Advertising

Google AdsEnterprise

Facebook PixelMid-Market

Ad platforms and retargeting pixels

Privacy & Cookies

Quantcast ChoiceMid-Market

Cookie consent and privacy compliance tools

Social Media

Facebook SDKFree

Twitter/X WidgetsFree

Social widgets and sharing tools

Sponsored

Scripts & Styles

23 Resources

Scripts

Styles

Async

Defer

Top Script Sources

hpx-cdn.xsd.cz(10)googletagmanager.com(2)s1.adform.net(1)pagead2.googlesyndication.com(1)ads.caroda.io(1)

Website Identity

X (Twitter)

Sponsored

Last analyzed: 19 Feb 2026 at 18:58

Historical Analysis & Change Tracking