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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eso.org

https://eso.org· First analyzed 17 Feb 2026· Updated 17 Feb 2026

Export

eso.org

Sponsored

Hosting Provider

ESO

IP Address

134.171.75.1

Server Location

🇩🇪 Garching, Germany

ASN

AS2117

Organization

ESO

Server

Nginx

Nameservers

dnsslave2.hq.eso.org.dnsslave1.hq.eso.org.dnsslave2.sc.eso.org.dnsslave1.sc.eso.org.

Performance

Page Speed

1.5 MB

38 requests

0–49

50–89

90–100

Architecture Stack

Monolithic

⚙️ SSR

Infrastructure

Hosting

ESO

Technology Stack

6 Technologies Detected

Meta Frameworks

Libraries

CSS Frameworks

Icon Libraries

Analytics

Web Servers

SEO Analysis

C68/100

eso.orgeso.org

ESO

ESO, European Organisation for Astronomical Research in the Southern Hemisphere

Title Length3 chars

Recommended: 50-60 chars

Description Length79 chars

Recommended: 120-160 chars

Issues (0)

5 issues found

Upgrade to view details

Crawlability

Sitemap

robots.txt

72 rules

Sponsored

Security Score

36%Critical

Interactive

HTTPS

No WAF

232d

Certificate Details

Type

Organization Validated (OV)

Certificate Authority

Hellenic Academic and Research Institutions CA

Key Algorithm

RSA (2048 bit)

Signature

SHA-256 with RSA

TLS Version

TLSv1.2

HTTP Protocol

HTTP/1.1

Valid From

08.10.2025

Valid Until

08.10.2026

OCSP Stapling

Enabled

Subject Alternative Names (20)

www.eso.orgcms-author2i.hq.eso.orgastronet.sc.eso.orgnext.eso.orgaaboard.eso.orgcms-pdispatch2.hq.eso.orgcms-pdispatch2i.hq.eso.orgcms-author.hq.eso.org+12 more

SHA-256 Fingerprint

CC:C3:56:5E:B6:B0:97:D8:02:AB:6A:0D:24:51:9A:60:C1:40:06:13...

Top Recommendations

Security recommendation preview

Upgrade to view recommendations

Upgrade to view header details

HTTP Headers

Developer Console

access-control-allow-origin

access-control-request-method

connection

keep-alive

content-encoding

📦 Gzip(gzip)

content-language

content-length

32880

Good Warning Issue

Email Infrastructure

Microsoft 365

Score

SPF

DKIM

DMARC

DMARC Policy

None (Monitor Only)

MX Records (1)

eso-org.mail.protection.outlook.com

Domain Information

eso.org

Domain Age

35 years

Created

06.02.1991

Expires

07.02.2031

Last Updated

20.11.2025

Registrar

Key-Systems GmbH

DNSSEC

Not Enabled

Privacy & Compliance

Cookie Consent Banner

GDPR Indicators

Data Protection Officer mentioned

Typography & Readability

Helvetica Neue LT ESO

66/100

Readability

/30

20/40

13px · LH 1.43

Hierarchy

/20

18/25

2.54x ratio

WCAG

/25

15/15

Contrast: undefined

Performance

/25

13/20

1 font

Heading Font

Helvetica Neue LT ESO

Sans33px

Body Font

Helvetica Neue LT ESO

Sans13px

Contrast Ratio

Reading Comfort

~50 CPL

Optimal (45–75)

33px

27px

13px

❌ Critical: 13px body text is too small. Increase to at least 14px.

✅ Optimal line spacing: 1.43 ratio ensures comfortable reading.

✅ Strong hierarchy: Headlines are 2.5x larger than body text.

✅ Good performance: Using 1 font families keeps load times fast.

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

✅ Optimal line length: ~50 characters per line is comfortable to read.

Buy on MyFonts

Business & Marketing Stack

2 Tools Detected

Growing

Behavior Analytics

Matomo (Piwik)Mid-Market

Google AnalyticsFree

User behavior and product analytics

Sponsored

Scripts & Styles

7 Resources

Scripts

Styles

Async

Defer

Top Script Sources

youtube.com(2)local(2)eso.org(1)

Website Identity

Facebook X (Twitter)Instagram LinkedIn YouTube Pinterest Mastodon Threads Bluesky

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Last analyzed: 17 Feb 2026 at 13:54

Historical Analysis & Change Tracking