openintro.org

https://openintro.org· First analyzed 22 May 2026· Updated 22 May 2026

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openintro.org

Mobile

Sponsored

Hosting Provider

HostGator

hostgator.com

IP Address

192.185.65.127

Site Location

🇺🇸 United Statesvia ip

Server Location

🇺🇸 Ashburn, United States

ASN

AS19871

Organization

HostGator.com LLC

Server

Apache

Nameservers

ns1630.hostgator.com.ns1629.hostgator.com.

Performance

Core Web Vitals

Weight

First Contentful Paint

1.2 s10%

Speed Index

1.5 s10%

Largest Contentful Paint

—25%

Total Blocking Time

0.0 ms30%

Cumulative Layout Shift

0.00025%

1.1 MB

23 requests

0–49

50–89

90–100

Architecture Stack

Monolithic

⚙️ SSR

Frontend

Styling

Tailwind CSS

Infrastructure

Hosting

HostGator

Technology Stack

7 Technologies Detected

Analytics

UI Components

CSS Frameworks

Icon Libraries

Web Servers

Libraries

SEO Analysis

D56/100

Meta Tags9/15

Content10/12

Headings7/8

Technical11/21

E-E-A-T0/7

Images4/7

Links3/5

URL5/5

Social0/5

Freshness0/4

Mobile4/4

Indexability3/3

openintro.orgopenintro.org

OpenIntro: developer and promoter of educational products that are ...

OpenIntro's mission is to make educational products that are free, transparent, and lower barriers to education. We're a registered 501(c)(3) nonprofit.

Title truncated.

Title Length118 chars

Recommended: 50-60 chars (~715px / 580px)

Description Length152 chars

Recommended: 120-160 chars

Issues (1)

• Title is too long (118 chars, ~715px). Will be truncated in search results.

8 issues found

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Local SEO

Local Search Readiness

6/100

Poor

2 13 2

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

Sponsored

AI & LLM Readiness

F34/100

Bot Access

20/25

Machine Read.

6/25

Schema Data

0/25

Citation

8/25

AI Bot Access

14/14 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

navheader/footer

Text ratio:10%

Words:268

Token eff.:Too Short

Sections/1K:3.7

Depth:2/5

Structured Data

No Schema

Citation Readiness

Opening Summary29w

Descriptive Headingsavg 2w

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.

82/100

Passed

Critical

Warnings

Images & Alt Text

20/20

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

Semantic Structure

17/20

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

6/15

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.

44/100

141 mg

CO₂e / view

1.1 MB

Page Weight

70%

Cleaner Than

New Visitor

161 mg

Returning (cached)

81 mg

Annual (10K/mo)

16.9 kg

Emission Segments

Data Center

32 mg

Network

34 mg

Device

76 mg

Resource Breakdown

JavaScript

146.2 KB

Images

229.9 KB

CSS

758.3 KB

HTML

5.3 KB

Green Hosting Not Verified

HostGator

4 recommendations

•Carbon footprint recommendation preview...

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Security Score

21%Critical

Interactive

HTTPS

No WAF

118d

Certificate Details

Type

Domain Validated (DV)

Certificate Authority

Sectigo Limited

Key Algorithm

RSA (2048 bit)

Signature

SHA-256 with RSA

TLS Version

TLSv1.3

HTTP Protocol

HTTP/2

Valid From

03.09.2025

Valid Until

17.09.2026

OCSP Stapling

Enabled

Subject Alternative Names (2)

openintro.orgwww.openintro.org

SHA-256 Fingerprint

03:75:4C:95:BA:ED:25:12:78:90:29:13:D5:AC:49:E2:4F:BC:C8:FA...

Top Recommendations

Security recommendation preview

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HTTP Headers

Developer Console

cache-control

🔴 No Cache(no-store, no-cache, must-revalidate)

content-encoding

📦 Gzip(gzip)

content-length

5086

content-type

text/html; charset=UTF-8

date

Fri, 22 May 2026 09:08:29 GMT

expires

Thu, 19 Nov 1981 08:52:00 GMT

Good Warning Issue

Email Infrastructure

Custom Mail Server

Score

SPF

DKIM

DMARC

MX Records (1)

openintro.org

Domain Information

openintro.org

Domain Age

16y 10m

Created

11.07.2009

Expires

11.07.2032

Last Updated

17.07.2025

Registrar

Squarespace Domains II LLC

DNSSEC

Not Enabled

Privacy & Compliance

Cookie Consent Banner

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.

63/100

Mobile Friendly1 breakpoint

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.

Viewport

width=device-width, initial-scale=1, shrink-to-fit=no

2 recommendations

•Mobile compatibility recommendation preview...

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Typography & Readability

Nunito

WCAG Partial

60/100

Readability

/30

24/30

18px · LH 1.70

Hierarchy

/20

9/20

2.22x ratio

WCAG

/25

12/25

1:1 min contrast

Performance

/25

15/25

1 font · 3 req

Heading Font

Nunito

Sans40px

Body Font

Nunito

Sans18px

Contrast Ratio

1:1

9 issues

Reading Comfort

~35 CPL

Narrow lines

40px

32px

24px

18px

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

⚠️ Hard to read: Flesch score 41/100. Simplify sentences for wider reach.

⚠️ Partial contrast: 9 elements below WCAG AA threshold (min 1.0:1).

❌ Missing H1: Every page should have exactly one H1 element for SEO and accessibility.

✅ Strong hierarchy: Headlines are 2.2x larger than body text.

❌ Pure vw font sizes: Viewport units alone break browser zoom (WCAG 1.4.4 fail). Use clamp(rem, vw, rem).

Buy on MyFontsFlesch 41

Color Palette

10 unique colors

Dark

#453d3a

Secondary· 26.200000000000003%

#273444

Primary· 16.1%

#dee8e1

Secondary· 15.100000000000001%

#063968

Primary· 13.8%

#eddb7a

Accent· 12.3%

#fdfdfc

Secondary· 6.1%

#0a5e8f

Accent· 4.2%

#9db39e

Secondary· 2.9%

Business & Marketing Stack

1 Tools Detected

Growing

Behavior Analytics

Google AnalyticsFree

User behavior and product analytics

Sponsored

Scripts & Styles

11 Resources

Scripts

Styles

Async

Defer

Top Script Sources

local(5)google-analytics.com(1)

Website Identity

openintro.org

16 years old

Location detected: 🇺🇸 United Statesvia ip

Squarespace Domains II LLCen

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Last analyzed: 22 May 2026 at 09:08

Historical Analysis & Change Tracking