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.

Back to Search

openlibrary.org

https://openlibrary.org· First analyzed 12 Feb 2026· Updated 12 Feb 2026

Export

openlibrary.org

Mobile

Sponsored

Hosting Provider

Internet Archive

IP Address

207.241.234.205

Server Location

🇺🇸 San Francisco, United States

ASN

AS7941

Organization

Internet Archive

Server

Nginx

Nameservers

ns3.archive.org.ns2.archive.org.ns1.archive.org.

Performance

Page Speed

306 KB

77 requests

Image Optimization

Lazy Load

0–49

50–89

90–100

Architecture Stack

Monolithic

⚙️ SSR

Ghost

Progressive Web App

Web ManifestApple Touch IconTheme Color

Technology Stack

3 Technologies Detected

Libraries

jQuery

CSS Frameworks

Tailwind CSS

Web Servers

Nginxv1.28.1

SEO Analysis

D52/100

openlibrary.orgopenlibrary.org

Welcome to Open Library | Open Library

Open Library is an open, editable library catalog, building towards a web page for every book ever published. Read, borrow, and discover more than 3M books f...

Description truncated.

Title Length38 chars

Recommended: 50-60 chars

Description Length165 chars

Recommended: 120-160 chars

Issues (1)

• Missing H1 tag - every page should have one H1

6 issues found

Upgrade to view details

Crawlability

Sitemap

robots.txt

41 rules

Sitemap reference found

Sponsored

Security Score

26%Critical

Interactive

HTTPS

No WAF

48d

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/2

Valid From

01.01.2026

Valid Until

01.04.2026

Subject Alternative Names (2)

openlibrary.orgwww.openlibrary.org

SHA-256 Fingerprint

5E:13:FA:90:1B:37:8C:07:DC:34:DE:7B:80:5D:6C:C6:36:79:77:B2...

Top Recommendations

Security recommendation preview

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Upgrade to view header details

HTTP Headers

Developer Console

content-encoding

📦 Gzip(gzip)

content-type

text/html; charset=utf-8

date

Thu, 12 Feb 2026 13:35:24 GMT

referrer-policy

no-referrer-when-downgrade

server

nginx/1.28.1

vary

Accept-Encoding

Good Warning Issue

Email Infrastructure

Custom Mail Server

Score

SPF

DKIM

DMARC

Domain Information

openlibrary.org

Domain Age

24y 7m

Created

25.06.2001

Expires

25.06.2027

Last Updated

08.07.2025

Registrar

easyDNS Technologies Inc.

DNSSEC

Not Enabled

Typography & Readability

-apple-system

66/100

Readability

/30

30/40

16px · LH --

Hierarchy

/20

8/25

WCAG

/25

15/15

Contrast: undefined

Performance

/25

20/20

System fonts

Heading Font

-apple-system

Sans

Body Font

-apple-system

Sans16px

Contrast Ratio

Reading Comfort

~39 CPL

Needs attention

16px

15px

16px

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

✅ 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.

⚠️ Cramped layout: 47 elements lack adequate spacing.

Business & Marketing Stack

1 Tools Detected

Growing

Behavior Analytics

Google AnalyticsFree

User behavior and product analytics

Sponsored

Scripts & Styles

5 Resources

Scripts

Styles

Async

Defer

Top Script Sources

local(3)apollo.archive.org(1)

Website Identity

X (Twitter)GitHub Bluesky

Sponsored

Last analyzed: 12 Feb 2026 at 13:35

Historical Analysis & Change Tracking