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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seznam.cz

https://seznam.cz· First analyzed 15 Feb 2026· Updated 15 Feb 2026

Export

seznam.cz

Mobile

Sponsored

Hosting Provider

Seznam - III

IP Address

77.75.77.222

Server Location

🇨🇿 Praha 10, Czechia

ASN

AS43037

Server

Envoy

Nameservers

ams.seznam.cz.ans.seznam.cz.

Performance

Page Speed

1.2 MB

250 requests

Image Optimization

Lazy LoadWebPResponsive

0–49

50–89

90–100

Architecture Stack

Headless

⚙️ SSR

Decoupled

Frontend

Styling

Tailwind CSS

API

Data Source

Headless CMS

Strapi

Infrastructure

Hosting

Seznam - III

Detected API Sources

https://login.szn.cz/js/api/3/...

Technology Stack

6 Technologies Detected

Analytics

CSS Frameworks

Meta Frameworks

SEO Analysis

D52/100

seznam.czseznam.cz

Seznam – najdu tam, co neznám

Nejnavštěvovanější český internetový portál nabízející vyhledávač, e-mail, aktuální zprávy, předpověď počasí a odkazy, které se mohou hodit.

Title Length29 chars

Recommended: 50-60 chars

Description Length140 chars

Recommended: 120-160 chars

Issues (2)

• Missing H1 tag - every page should have one H1
• Many images missing alt text (191/249)

5 issues found

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Crawlability

Sitemap

Type: standard

robots.txt

40 rules

Sitemap reference found

Sponsored

Security Score

66%Fair

Interactive

HTTPS

No WAF

77d

Certificate Details

Type

Domain Validated (DV)

Certificate Authority

Let's Encrypt

Key Algorithm

RSA (4096 bit)

Signature

SHA-256 with RSA

TLS Version

TLSv1.3

HTTP Protocol

HTTP/2

Valid From

02.02.2026

Valid Until

03.05.2026

Subject Alternative Names (18)

admin.seznam.czadmin100-api.seznam.czadmin100-node.seznam.czadmin100.seznam.czapi.seznam.czapi2.seznam.czfallback.seznam.czladime.seznam.cz+10 more

SHA-256 Fingerprint

3A:AB:8C:BC:69:B3:8B:FC:C8:99:3C:1E:11:81:E8:0D:3B:B6:5D:50...

Top Recommendations

Security recommendation preview

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HTTP Headers

Developer Console

cache-control

🔴 No Cache(no-cache, no-store, must-revalidate)

content-encoding

📦 Gzip(gzip)

content-security-policy

frame-ancestors 'self'

content-type

text/html; charset=UTF-8

date

Sun, 15 Feb 2026 06:21:10 GMT

pragma

no-cache

Good Warning Issue

Email Infrastructure

Custom Mail Server

Score

SPF

DKIM

DMARC

DMARC Policy

None (Monitor Only)

MX Records (2)

mx2.seznam.cz

mx1.seznam.cz

Domain Information

seznam.cz

Domain Age

29y 4m

Created

07.10.1996

Expires

28.10.2026

Last Updated

05.09.2022

Registrar

REG-SEZNAM

DNSSEC

Not Enabled

Privacy & Compliance

Cookie Consent Banner

GDPR Indicators

Data Protection Officer mentioned

Typography & Readability

Arial

68/100

Readability

/30

32/40

16px · LH 1.25

Hierarchy

/20

8/25

1x ratio

WCAG

/25

15/15

Contrast: undefined

Performance

/25

20/20

System fonts

Heading Font

Arial

Sans16px

Body Font

Arial

Sans16px

Contrast Ratio

Reading Comfort

~45 CPL

Optimal (45–75)

16px

14px

16px

Minor Second

Scale

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

⚠️ Weak hierarchy: Headlines should be at least 2x body size for clear visual structure.

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

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

✅ Protected text on images: Using gradient for readability.

✅ Optimal line length: ~45 characters per line is comfortable to read.

Business & Marketing Stack

3 Tools Detected

Advanced

Behavior Analytics

Google AnalyticsFree

Google Tag ManagerFree

User behavior and product analytics

Privacy & Cookies

Quantcast ChoiceMid-Market

Cookie consent and privacy compliance tools

Sponsored

Scripts & Styles

25 Resources

Scripts

Styles

Async

Defer

Top Script Sources

local(4)h.seznam.cz(4)d53-a.sdn.cz(3)spir.hit.gemius.pl(2)login.szn.cz(1)

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Last analyzed: 15 Feb 2026 at 06:21

Historical Analysis & Change Tracking