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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cervantesvirtual.com

https://cervantesvirtual.com· First analyzed 17 Feb 2026· Updated 17 Feb 2026

Export

Sponsored

Hosting Provider

Asac Comunicaciones S.L.

IP Address

46.24.172.11

Server Location

🇪🇸 Vigo, Spain

ASN

AS12430

Organization

Asac Comunicaciones S.L.

Server

Apache

Nameservers

oxygen.ns.hetzner.com.helium.ns.hetzner.de.hydrogen.ns.hetzner.com.

Performance

Page Speed

1.9 MB

50 requests

0–49

50–89

90–100

Architecture Stack

Monolithic

⚙️ SSR

Frontend

Framework

jQuery

Styling

Bootstrap

Infrastructure

Hosting

Asac Comunicaciones S.L.

Technology Stack

14 Technologies Detected

Analytics

Google Analytics

Google Analytics 4

Facebook Pixel Segment

Meta Frameworks

Libraries

UI Components

Other

CSS Frameworks

Icon Libraries

Fonts

Web Servers

Languages

Customer Support

SEO Analysis

A84/100

cervantesvirtual.comcervantesvirtual.com

Biblioteca Virtual Miguel de Cervantes | Inicio

La Biblioteca Virtual Miguel de Cervantes, la primera en lengua castellana, es un fondo bibliográfico con obras de Literatura, Historia, Ciencias, etc., de l...

Description truncated.

Title Length47 chars

Recommended: 50-60 chars

Description Length254 chars

Recommended: 120-160 chars

Issues (0)

2 issues found

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Crawlability

Sitemap

robots.txt

11 rules

Sponsored

Security Score

21%Critical

Interactive

HTTPS

No WAF

62d

Certificate Details

Type

Domain Validated (DV)

Certificate Authority

Let's Encrypt

Key Algorithm

RSA (2048 bit)

Signature

SHA-256 with RSA

TLS Version

TLSv1.3

HTTP Protocol

HTTP/1.1

Valid From

21.01.2026

Valid Until

21.04.2026

Subject Alternative Names (2)

*.cervantesvirtual.comcervantesvirtual.com

SHA-256 Fingerprint

9C:D7:B0:65:24:DC:2E:85:47:78:18:3C:FA:23:1F:DA:2F:C5:6B:30...

Top Recommendations

Security recommendation preview

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HTTP Headers

Developer Console

cache-control

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

content-encoding

📦 Gzip(gzip)

content-length

10019

content-type

text/html; charset=UTF-8

date

Tue, 17 Feb 2026 16:30:50 GMT

expires

Thu, 19 Nov 1981 08:52:00 GMT

Good Warning Issue

Email Infrastructure

Google Workspace

Score

SPF

DKIM

DMARC

MX Records (7)

alt1.aspmx.l.google.com

aspmx3.googlemail.com

aspmx4.googlemail.com

aspmx2.googlemail.com

+3 more

Domain Information

cervantesvirtual.com

Domain Age

26y 7m

Created

01.07.1999

Expires

01.07.2027

Last Updated

14.01.2026

Registrar

Nominalia Internet SL

DNSSEC

Not Enabled

Privacy & Compliance

Cookie Consent Banner

GDPR Indicators

Cookie consent banner detected

Data Protection Officer mentioned

Typography & Readability

sans-serif

53/100

Readability

/30

32/40

14px · LH 1.67

Hierarchy

/20

11/25

1.39x ratio

WCAG

/25

5/15

Contrast: undefined

Performance

/25

20/20

System fonts

Heading Font

sans-serif

Sans20px

Body Font

sans-serif

Sans14px

Contrast Ratio

Reading Comfort

~32 CPL

Needs attention

20px

40px

19px

14px

Major Third

Scale

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

✅ Optimal line spacing: 1.67 ratio ensures comfortable reading.

⚠️ 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.

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

Business & Marketing Stack

5 Tools Detected

Enterprise

Behavior Analytics

Google AnalyticsFree

Google Tag ManagerFree

User behavior and product analytics

Advertising

Facebook PixelMid-Market

Ad platforms and retargeting pixels

Social Media

Facebook SDKFree

Twitter/X WidgetsFree

Social widgets and sharing tools

Sponsored

Scripts & Styles

13 Resources

Scripts

Styles

Async

Defer

Top Script Sources

local(8)google-analytics.com(1)googletagmanager.com(1)connect.facebook.net(1)

Website Identity

Facebook X (Twitter)

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Last analyzed: 17 Feb 2026 at 16:30

Historical Analysis & Change Tracking