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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penguinrandomhouse.com

https://penguinrandomhouse.com· First analyzed 11 Feb 2026· Updated 11 Feb 2026

Export

Mobile

Sponsored

Hosting Provider

Random House, Inc.

IP Address

170.171.208.137

Server Location

🇺🇸 New York, United States

ASN

AS11790

Organization

Random House, Inc.

Server

Nginx

CDN

CloudFront

Nameservers

ns-1259.awsdns-29.org.ns-1709.awsdns-21.co.uk.ns-362.awsdns-45.com.ns-643.awsdns-16.net.

Performance

Page Speed

1.1 MB

133 requests

0–49

50–89

90–100

Architecture Stack

Monolithic

⚙️ SSR

Frontend

Framework

React

CMS

WordPressv6.8.3

Infrastructure

Hosting

Random House, Inc.

CDN

CloudFront

Technology Stack

6 Technologies Detected

Frameworks

Libraries

UI Components

CSS Frameworks

Icon Libraries

Web Servers

SEO Analysis

A82/100

penguinrandomhouse.compenguinrandomhouse.com

Penguin Random House

Committed to publishing great books, connecting readers and authors globally, and spreading the love of reading.

Title Length20 chars

Recommended: 50-60 chars

Description Length112 chars

Recommended: 120-160 chars

Issues (0)

3 issues found

Upgrade to view details

Sponsored

Security Score

71%Good

Interactive

HTTPS

No WAF

332d

Top Recommendations

Security recommendation preview

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Upgrade to view header details

HTTP Headers

Developer Console

alt-svc

h3=":443"; ma=86400

content-encoding

📦 Gzip(gzip)

content-security-policy

frame-ancestors 'self' https://cart.penguinrandomhouse.com/ ...

content-type

text/html; charset=UTF-8

date

Wed, 11 Feb 2026 08:16:26 GMT

referrer-policy

strict-origin

Good Warning Issue

Typography & Readability

Fort-Light + Fort-Medium

46/100

Readability

/30

32/40

18px · LH 1.33

Hierarchy

/20

16/25

1.78x ratio

WCAG

/25

5/15

Contrast: undefined

Performance

/25

10/20

4 fonts

Heading Font

Fort-Light

Sans32px

Body Font

Fort-Medium

Sans18px

Contrast Ratio

Reading Comfort

~41 CPL

Needs attention

32px

16px

18px

✅ Excellent readability: 18px body text is ideal for all devices.

✅ Good hierarchy: Clear distinction between headlines and body text.

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

⚠️ Risky: Text appears on background images without overlay protection.

⚠️ Cramped layout: 18 elements lack adequate spacing.

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Business & Marketing Stack

1 Tools Detected

Growing

Behavior Analytics

Google AnalyticsFree

User behavior and product analytics

Sponsored

Scripts & Styles

30 Resources

Scripts

Styles

Async

Defer

Top Script Sources

local(8)penguinrandomhouse.com(5)tags.tiqcdn.com(4)rum-static.pingdom.net(1)ajax.googleapis.com(1)

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Last analyzed: 11 Feb 2026 at 08:16

Historical Analysis & Change Tracking