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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casadellibro.com

https://casadellibro.com· First analyzed 16 Feb 2026· Updated 16 Feb 2026

Export

casadellibro.com

Sponsored

Hosting Provider

COLT Telecom

IP Address

212.0.104.156

Server Location

🇪🇸 Barcelona, Spain

ASN

AS8220

Organization

COLT Telecom

Server

Apache

Nameservers

ns1.acens.net.ns2.acens.net.ns2.dominioabsoluto.com.ns1.dominioabsoluto.com.

Performance

Page Speed

402 KB

200 requests

Image Optimization

Lazy LoadWebPResponsive

0–49

50–89

90–100

Architecture Stack

Monolithic

⚙️ SSR

Infrastructure

Hosting

COLT Telecom

Technology Stack

10 Technologies Detected

Analytics

Frameworks

Meta Frameworks

CSS Frameworks

Fonts

Tag Managers

Other

Web Servers

SEO Analysis

A88/100

casadellibro.comcasadellibro.com

Compra libros, eBooks y audiolibros | Librería Casa del Libro

Descubre todas las novedades en libros y bestsellers con envíos rápidos. Compra al mejor precio. La librería online con más de 70 tiendas.

Title Length61 chars

Recommended: 50-60 chars

Description Length139 chars

Recommended: 120-160 chars

Issues (0)

2 issues found

Upgrade to view details

Crawlability

Sitemap

Type: index

16 URLs

robots.txt

1430 rules

Sitemap reference found

Sponsored

Security Score

76%Good

Interactive

HTTPS

No WAF

45d

Certificate Details

Type

Domain Validated (DV)

Certificate Authority

Let's Encrypt

Key Algorithm

ECDSA (secp256r1) (256 bit)

Signature

ECDSA with SHA-384

TLS Version

TLSv1.3

HTTP Protocol

HTTP/2+H3

Valid From

03.01.2026

Valid Until

03.04.2026

Subject Alternative Names (1)

www.casadellibro.com

SHA-256 Fingerprint

B5:9F:1A:21:CA:B9:80:CB:05:5B:AA:68:74:5F:B3:24:60:9D:C8:53...

Top Recommendations

Security recommendation preview

Upgrade to view recommendations

Upgrade to view header details

HTTP Headers

Developer Console

access-control-allow-credentials

true

access-control-allow-headers

origin,range,hdntl,hdnts,CMCD-Request,CMCD-Object,CMCD-Statu...

access-control-allow-methods

GET,POST,OPTIONS

access-control-allow-origin

access-control-expose-headers

Server,range,hdntl,hdnts,Akamai-Mon-Iucid-Ing,Akamai-Mon-Iuc...

akamai-grn

0.673319b8.1771277621.20dc8054

Good Warning Issue

Email Infrastructure

Custom Mail Server

Score

SPF

DKIM

DMARC

DMARC Policy

Quarantine (Moderate)

MX Records (4)

poster2i.iberlayer.com

poster3i.iberlayer.com

poster1i.iberlayer.com

poster4i.iberlayer.com

Domain Information

casadellibro.com

Domain Age

28y 2m

Created

04.12.1997

Expires

03.12.2026

Last Updated

14.11.2025

Registrar

Nominalia Internet SL

DNSSEC

Not Enabled

Privacy & Compliance

OneTrust

Cookie Consent Banner

OneTrust

GDPR Indicators

Cookie consent banner detected

CMP: OneTrust

Data Protection Officer mentioned

Typography & Readability

Source Sans Pro

71/100

Readability

/30

40/40

16px · LH 1.50

Hierarchy

/20

8/25

1.25x ratio

WCAG

/25

15/15

Contrast: undefined

Performance

/25

13/20

2 fonts

Heading Font

Source Sans Pro

Sans20px

Body Font

Source Sans Pro

Sans16px

Contrast Ratio

Reading Comfort

~36 CPL

Needs attention

20px

24px

16px

Major Second

Scale

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

✅ Optimal line spacing: 1.50 ratio ensures comfortable reading.

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

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

✅ 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.

Buy on MyFonts

Business & Marketing Stack

6 Tools Detected

Enterprise

Behavior Analytics

Microsoft ClarityFree

Google Tag ManagerFree

Google AnalyticsFree

User behavior and product analytics

Privacy & Cookies

OneTrustEnterprise

Cookie consent and privacy compliance tools

A/B Testing & Optimization

AB TastyMid-Market

Experimentation and conversion optimization

Reviews & Social Proof

TrustpilotMid-Market

Customer reviews and testimonials

Sponsored

Scripts & Styles

21 Resources

Scripts

Styles

Async

Defer

Top Script Sources

googletagmanager.com(10)local(2)scripts.clarity.ms(1)clarity.ms(1)x.empathy.co(1)

Website Identity

Facebook X (Twitter)Instagram YouTube TikTok

Sponsored

Last analyzed: 16 Feb 2026 at 21:33

Historical Analysis & Change Tracking