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

pdflib.com

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

Export

pdflib.com

Mobile

Sponsored

Hosting Provider

IONOS (1&1)

ionos.com

IP Address

217.160.0.96

Server Location

🇩🇪 Essen, Germany

ASN

AS8560

Organization

Ionos Inf

Server

Apache

Nameservers

ns1096.ui-dns.org.ns1111.ui-dns.biz.ns1028.ui-dns.de.ns1042.ui-dns.com.

Performance

Page Speed

340 KB

15 requests

0–49

50–89

90–100

Architecture Stack

Monolithic

⚙️ SSR

TYPO3

Technology Stack

7 Technologies Detected

Analytics

Libraries

CSS Frameworks

Tag Managers

Web Servers

Security

SEO Analysis

D47/100

pdflib.compdflib.com

PDFlib: PDFlib GmbH Home

No description available for this page.

Title Length24 chars

Recommended: 50-60 chars

Description Length0 chars

Recommended: 120-160 chars

Issues (2)

• Missing meta description - important for click-through rates
• Many images missing alt text (7/7)

6 issues found

Upgrade to view details

Sponsored

Security Score

21%Critical

Interactive

HTTPS

No WAF

150d

Certificate Details

Type

Domain Validated (DV)

Certificate Authority

Sectigo Limited

Key Algorithm

RSA (2048 bit)

Signature

SHA-256 with RSA

TLS Version

TLSv1.2

HTTP Protocol

HTTP/2

Valid From

27.06.2025

Valid Until

11.07.2026

OCSP Stapling

Enabled

Subject Alternative Names (2)

*.pdflib.compdflib.com

SHA-256 Fingerprint

36:20:3E:2E:84:FA:F3:2D:E0:3A:48:B3:5C:CE:2E:FB:87:F2:30:AB...

Top Recommendations

Security recommendation preview

Upgrade to view recommendations

Upgrade to view header details

HTTP Headers

Developer Console

cache-control

🔴 No Cache(private, no-store)

content-encoding

📦 Gzip(gzip)

content-language

content-type

text/html; charset=utf-8

date

Wed, 11 Feb 2026 11:03:48 GMT

server

Apache

Good Warning Issue

Email Infrastructure

Microsoft 365

Score

SPF

DKIM

DMARC

DMARC Policy

Quarantine (Moderate)

MX Records (1)

pdflib-com.mail.protection.outlook.com

Privacy & Compliance

Cookie Consent Banner

GDPR Indicators

Cookie consent banner detected

Typography & Readability

The Sans

53/100

Readability

/30

32/40

14px · LH 1.43

Hierarchy

/20

20/25

1.57x ratio

WCAG

/25

5/15

Contrast: undefined

Performance

/25

13/20

1 font

Heading Font

The Sans

Sans22px

Body Font

The Sans

Sans14px

Contrast Ratio

Reading Comfort

~40 CPL

Needs attention

22px

20px

14px

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

✅ Optimal line spacing: 1.43 ratio ensures comfortable reading.

✅ Good hierarchy: Clear distinction between headlines and 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.

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

Buy on MyFonts

Business & Marketing Stack

2 Tools Detected

Growing

Behavior Analytics

Google Tag ManagerFree

Google AnalyticsFree

User behavior and product analytics

Sponsored

Scripts & Styles

5 Resources

Scripts

Styles

Async

Defer

Top Script Sources

local(1)pdflib.com(1)assets(1)

Sponsored

Last analyzed: 11 Feb 2026 at 11:03

Historical Analysis & Change Tracking