usaco.org

https://usaco.org· First analyzed 25 May 2026· Updated 25 May 2026

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usaco.org

Mobile

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Hosting Provider

Cloudflare

cloudflare.com

IP Address

104.21.78.228

Site Location

🇨🇦 Canadavia ip

Server Location

🇨🇦 Toronto, Canada

ASN

AS13335

Organization

Cloudflare, Inc.

Server

Cloudflare

CDN

Cloudflare

WAF

Cloudflare

Nameservers

andronicus.ns.cloudflare.com.aurora.ns.cloudflare.com.

Performance

100

Core Web Vitals

Weight

First Contentful Paint

252 ms10%

Speed Index

328 ms10%

Largest Contentful Paint

—25%

Total Blocking Time

0.0 ms30%

Cumulative Layout Shift

0.00025%

4 KB

10 requests

0–49

50–89

90–100

Architecture Stack

Monolithic

⚙️ SSR

Infrastructure

Hosting

Cloudflare

CDN

Cloudflare

Technology Stack

3 Technologies Detected

Libraries

jQuery

CDN

Cloudflare

Customer Support

Zendesk

SEO Analysis

F39/100

Meta Tags4/15

Content11/12

Headings3/8

Technical4/21

E-E-A-T0/7

Images1/7

Links5/5

URL5/5

Social0/5

Freshness0/4

Mobile3/4

Indexability3/3

usaco.orgusaco.org

USACO

No description available for this page.

Title Length5 chars

Recommended: 50-60 chars (~33px / 580px)

Description Length0 chars

Recommended: 120-160 chars

Issues (4)

• Missing meta description — important for click-through rates in SERPs
• Missing H1 tag — every page should have exactly one H1
• Most images missing alt text (4/4) — critical for accessibility and SEO

16 issues found

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Local SEO

Local Search Readiness

0/100

Poor

15 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

F33/100

Bot Access

20/25

Machine Read.

8/25

Schema Data

0/25

Citation

5/25

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

Text ratio:21%

Words:653

Token eff.:Optimal

Sections/1K:12.3

Structured Data

No Schema

Citation Readiness

Opening Summary63w

Descriptive Headingsavg 3.1w

Canonical URL

Open Graph0/3

Twitter Card0/3

Language Tag

Publish Date

Author Info

Lists

Tables

TL;DR / Summary

About Page Link

Recommendations (12)

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.

39/100

Passed

Critical

Warnings

Images & Alt Text

5/20

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

Semantic Structure

4/20

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

Forms & Inputs

8/15

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

Color & Contrast

14/15

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

Keyboard & Focus

7/15

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.

5 recommendations

•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.

64/100

A+

<0.001 g

CO₂e / view

3.9 KB

Page Weight

95%

Cleaner Than

New Visitor

<0.001 g

Returning (cached)

<0.001 g

Annual (10K/mo)

48 g

Emission Segments

Data Center

<0.001 g

Network

<0.001 g

Device

<0.001 g

Resource Breakdown

HTML

3.9 KB

Green Hosting Verified

Cloudflare

GWF Verified

4 recommendations

•Carbon footprint recommendation preview...

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Security Score

0%Critical

Critical / Transactional

HTTPS

WAF

84d

Certificate Details

Type

Domain Validated (DV)

Certificate Authority

Google Trust Services

Key Algorithm

ECDSA (secp256r1) (256 bit)

Signature

ECDSA with SHA-256

TLS Version

TLSv1.3

HTTP Protocol

HTTP/2+H3

Valid From

19.05.2026

Valid Until

17.08.2026

OCSP Stapling

Enabled

Subject Alternative Names (2)

usaco.org*.usaco.org

SHA-256 Fingerprint

03:E8:E1:78:F1:80:F0:52:A6:43:94:43:DC:EF:16:2E:E5:C7:4F:99...

Top Recommendations

Security recommendation preview

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HTTP Headers

Developer Console

alt-svc

h3=":443"; ma=86400

cache-control

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

cf-cache-status

DYNAMIC

cf-ray🇩🇪 Frankfurt

a010e3b2c96cbbb6-FRA

content-encoding

zstd

content-type

text/html; charset=UTF-8

Good Warning Issue

Email Infrastructure

Custom Mail Server

Score

SPF

DKIM

DMARC

DMARC Policy

None (Monitor Only)

Domain Information

usaco.org

Domain Age

29y 8m

Created

05.09.1996

Expires

04.09.2029

Last Updated

24.08.2025

Registrar

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.

36/100

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.

3 recommendations

•Mobile compatibility recommendation preview...

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Typography & Readability

Arial

WCAG AAA

70/100

Readability

/30

18/30

14px · LH --

Hierarchy

/20

8/20

WCAG

/25

24/25

9.25:1 min contrast

Performance

/25

20/25

System fonts

Heading Font

Arial

Sans

Body Font

Arial

Sans14px

Contrast Ratio

9.25:1

WCAG AAA (≥7:1)

Reading Comfort

~68 CPL

Optimal (45–75)

21px

14px

⚠️ Small text: 14px may strain on mobile. Use ≥16px for WCAG compliance.

✅ Optimal line length: ~68 chars/line (ideal 45–75 CPL).

⚠️ Hard to read: Flesch score 32/100. Simplify sentences for wider reach.

✅ WCAG AAA contrast: All text meets 7:1 ratio (min 9.2:1).

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

✅ System fonts: Zero font loading delay — best possible LCP impact.

Flesch 32

Color Palette

10 unique colors

2.32:1 Fail Light

#ffffff

Background· 35.6%

#aaaaaa

Other· 33.3%

#232129

Primary· 7%

#ac6624

Accent· 6.5%

#884550

Secondary· 4.7%

#793245

Secondary· 4.1%

#8d796f

Border· 3%

#b48b68

Secondary· 1.1%

Business & Marketing Stack

1 Tools Detected

Growing

Behavior Analytics

Google AnalyticsFree

User behavior and product analytics

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Scripts & Styles

4 Resources

Scripts

Styles

Async

Defer

Top Script Sources

current(1)d3js.org(1)cdnjs.cloudflare.com(1)

Website Identity

usaco.org

29 years old

Location detected: 🇨🇦 Canadavia ip

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Last analyzed: 25 May 2026 at 01:51

Historical Analysis & Change Tracking