horstmann.com

https://horstmann.com· First analyzed 19 May 2026· Updated 19 May 2026

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horstmann.com

Mobile

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Hosting Provider

A2 Hosting, Inc

IP Address

68.66.226.114

Site Location

🇺🇸 United Statesvia ip

Server Location

🇺🇸 Phoenix, United States

ASN

AS55293

Organization

A2 Hosting, Inc

Server

Apache

Nameservers

ns2.hover.com.ns1.hover.com.

Performance

Core Web Vitals

Weight

First Contentful Paint

741 ms10%

Speed Index

963 ms10%

Largest Contentful Paint

—25%

Total Blocking Time

0.0 ms30%

Cumulative Layout Shift

0.00025%

6.9 MB

11 requests

Image Optimization

Lazy Load

0–49

50–89

90–100

Architecture Stack

Monolithic

⚙️ SSR

Infrastructure

Hosting

A2 Hosting, Inc

Technology Stack

1 Technologies Detected

Web Servers

Apache

SEO Analysis

D51/100

Meta Tags4/15

Content10/12

Headings8/8

Technical9/25

E-E-A-T0/7

Images3/7

Links5/5

URL5/5

Social0/5

Freshness0/4

Mobile4/4

Indexability3/3

horstmann.comhorstmann.com

Cay Horstmann's Home Page

No description available for this page.

Title Length25 chars

Recommended: 50-60 chars (~158px / 580px)

Description Length0 chars

Recommended: 120-160 chars

Issues (2)

• Missing meta description — important for click-through rates in SERPs
• Missing viewport meta tag — page may not be mobile-friendly (Google uses mobile-first indexing)

11 issues found

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Crawlability

Sitemap

robots.txt

18 rules

Local SEO

Local Search Readiness

5/100

Poor

2 13 2

This site doesn't appear to be a local business. Local SEO signals are optional for non-local websites.

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AI & LLM Readiness

F38/100

Bot Access

18/25

Machine Read.

14/25

Schema Data

0/25

Citation

6/25

AI Bot Access

12/14 accessible

AI Search

OAI-SearchBot

PerplexityBot

Claude-SearchBot

Gemini-Deep-Research

DuckAssistBot

Training

GPTBot

ClaudeBot

Google-Extended

Meta-ExternalAgent

Bytespiderinfo

Amazonbot

Applebot-Extended

CCBotinfo

Fetch

ChatGPT-User

Machine Readability

llms.txt

llms-full.txt

Semantic HTML

Heading Hierarchy

code blocksdef. lists

Text ratio:47%

Words:492

Token eff.:Optimal

Sections/1K:14.2

Depth:2/5

Structured Data

No Schema

Citation Readiness

Opening Summary119w

Descriptive Headingsavg 2.4w

Canonical URL

Open Graph0/3

Twitter Card0/3

Language Tag

Publish Date

Author Info

Lists

Tables

TL;DR / Summary

About Page Link

Recommendations (9)

AI readiness recommendation preview...

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Accessibility

WCAG 2.1 Compliance

Evaluates how accessible your website is for users with disabilities, based on WCAG 2.1 guidelines. Checks images, forms, keyboard navigation, ARIA roles, and color contrast.

74/100

Passed

Critical

Warnings

Images & Alt Text

20/20

Checks if images have descriptive alt text for screen readers and visually impaired users.

Semantic Structure

14/20

Evaluates proper use of HTML5 semantic elements (header, nav, main, footer) and heading hierarchy.

Forms & Inputs

15/15

Verifies form fields have labels, error messages are clear, and inputs are properly associated.

Color & Contrast

15/15

Tests text-to-background color contrast ratios against WCAG AA/AAA minimum requirements.

Keyboard & Focus

9/15

Ensures all interactive elements are reachable and operable via keyboard (tab, enter, escape).

ARIA & Roles

1/15

Checks correct use of WAI-ARIA attributes (roles, states, properties) for assistive technologies.

1 recommendation

•Accessibility recommendation preview...

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Carbon Footprint

SWDM v4 · Eco-Score

Carbon emissions estimated using the Sustainable Web Design Model v4 (SWDM v4). Factors in data center, network, and device energy across new and returning visitors. Grade thresholds based on HTTP Archive percentiles.

42/100

710 mg

CO₂e / view

6.9 MB

Page Weight

Cleaner Than

New Visitor

811 mg

Returning (cached)

406 mg

Annual (10K/mo)

85.2 kg

Emission Segments

Data Center

35 mg

Network

209 mg

Device

466 mg

Resource Breakdown

Images

67.8 KB

CSS

6.8 MB

HTML

3.1 KB

Green Hosting Verified

A2 Hosting, Inc

Provider Match

4 recommendations

•Carbon footprint recommendation preview...

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Security Score

86%Very Good

Static / Informational

HTTPS

No WAF

38d

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

28.03.2026

Valid Until

26.06.2026

Subject Alternative Names (2)

horstmann.comwww.horstmann.com

SHA-256 Fingerprint

06:09:4B:DB:3F:0A:C7:67:B4:31:CD:0D:0F:76:5C:F5:D5:FE:55:F4...

Recommendations

Security recommendation preview

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HTTP Headers

Developer Console

accept-ranges

bytes

access-control-allow-origin

cache-control

🟡 1 Hours(max-age=3600, must-revalidate)

connection

Keep-Alive

content-encoding

📦 Gzip(gzip)

content-length

2897

Good Warning Issue

Email Infrastructure

Fastmail

Score

SPF

DKIM

DMARC

MX Records (2)

in1-smtp.messagingengine.com

in2-smtp.messagingengine.com

Domain Information

horstmann.com

Domain Age

32y 9m

Created

19.08.1993

Expires

18.08.2026

Last Updated

17.08.2025

Registrar

Tucows Domains Inc.

DNSSEC

Not Enabled

Mobile Compatibility

Viewport & Responsive Test

Tests how well your website works on mobile devices. Checks viewport configuration, responsive layout, touch targets, font readability, and simulates rendering across different screen sizes.

39/100

Not Mobile Friendly

Viewport Meta

The viewport meta tag tells mobile browsers how to scale the page. Without it, mobile devices render at desktop width.

Responsive Design

Uses CSS media queries or flexible layouts to adapt content to different screen sizes automatically.

Touch Icons

Apple touch icons and favicons displayed when users add the site to their home screen on mobile devices.

Readable Font Size

Base font size should be at least 16px on mobile to ensure text is readable without zooming.

Relative Units

Using em, rem, %, or vw instead of fixed px values allows content to scale properly across screen sizes.

No H-Scroll Risk

No elements wider than the viewport that would cause horizontal scrolling on mobile devices.

Tap Targets OK

Interactive elements (buttons, links) are at least 48x48px with enough spacing to prevent accidental taps.

No Fixed Widths

No elements with fixed pixel widths that could overflow on smaller screens and break the layout.

2 recommendations

•Mobile compatibility recommendation preview...

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Typography & Readability

Title + Serif

WCAG AAA

79/100

Readability

/30

27/30

21px · LH 1.43

Hierarchy

/20

19/20

2x ratio · ✓ H1→H6

WCAG

/25

20/25

7.5:1 min contrast

Performance

/25

13/25

1 font · 4 req

Heading Font

Title

Sans42px

Body Font

Serif

Serif21px

Contrast Ratio

7.5:1

WCAG AAA (≥7:1)

Reading Comfort

Sans Headlines + Serif Body

left aligned

42px

31px

25px

21px

✅ Excellent readability: 21px body text is ideal for all devices.

✅ Optimal line spacing: 1.43 ratio (ideal range 1.4–1.6).

⚠️ Hard to read: Flesch score 46/100. Simplify sentences for wider reach.

✅ WCAG AAA contrast: All text meets 7:1 ratio (min 7.5:1).

✅ Perfect heading hierarchy: Sequential h1→h2→h3 with single H1 — ideal for SEO & accessibility.

✅ Strong hierarchy: Headlines are 2.0x larger than body text.

Buy on MyFontsFlesch 47

Color Palette

10 unique colors

13.62:1 AAA Light

#ffffff

Background· 83.4%

#302d2f

Other· 1.3%

#c3c8cf

Primary· 1.7%

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Scripts & Styles

2 Resources

Scripts

Styles

Async

Defer

Top Script Sources

gc.zgo.at(1)

Website Identity

horstmann.com

cay@horstmann.com

32 years old

Location detected: 🇺🇸 United Statesvia ip

Tucows Domains Inc.📧 Fastmailen

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Last analyzed: 19 May 2026 at 06:48

Historical Analysis & Change Tracking