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

yarnpkg.com

https://yarnpkg.com· First analyzed 13 Feb 2026· Updated 13 Feb 2026

Export

yarnpkg.com

Mobile

Sponsored

Hosting Provider

Cloudflare

cloudflare.com

IP Address

104.16.169.120

Server Location

🇨🇦 Toronto, Canada

ASN

AS13335

Organization

Cloudflare, Inc.

Server

Cloudflare

CDN

Cloudflare

WAF

Cloudflare

Nameservers

linda.ns.cloudflare.com.arnold.ns.cloudflare.com.

Performance

Page Speed

2.2 MB

59 requests

0–49

50–89

90–100

Architecture Stack

Monolithic

⚙️ SSR

Infrastructure

Hosting

Cloudflare

CDN

Cloudflare

Technology Stack

4 Technologies Detected

Other

Other

CSS Frameworks

CDN

SEO Analysis

D58/100

yarnpkg.comyarnpkg.com

Home page | Yarn

Yarn, the modern JavaScript package manager

Title Length16 chars

Recommended: 50-60 chars

Description Length43 chars

Recommended: 120-160 chars

Issues (1)

• Many images missing alt text (6/7)

4 issues found

Upgrade to view details

Crawlability

Sitemap

Type: standard

robots.txt

Sponsored

Security Score

71%Good

Static / Informational

HTTPS

WAF

71d

Certificate Details

Type

Domain Validated (DV)

Certificate Authority

Google Trust Services

Key Algorithm

ECDSA (secp256r1) (256 bit)

Signature

ECDSA with SHA-256

TLS Version

TLSv1.2

HTTP Protocol

HTTP/2

Valid From

26.01.2026

Valid Until

26.04.2026

OCSP Stapling

Enabled

Subject Alternative Names (2)

yarnpkg.com*.yarnpkg.com

SHA-256 Fingerprint

2D:B0:11:8B:28:4B:59:2B:5C:75:50:16:DE:B2:04:AA:02:9D:F9:A2...

Recommendations

Security recommendation preview

Upgrade to view recommendations

Upgrade to view header details

HTTP Headers

Developer Console

age

11845

cache-control

🟡 0s(public,max-age=0,must-revalidate)

cache-status

"Netlify Edge"; hit

cf-cache-status

DYNAMIC

cf-ray🇩🇪 Frankfurt

9cd6c3724d6fd2f6-FRA

content-encoding

📦 Gzip(gzip)

Good Warning Issue

Email Infrastructure

Custom Mail Server

Score

SPF

DKIM

DMARC

MX Records (3)

route3.mx.cloudflare.net

route1.mx.cloudflare.net

route2.mx.cloudflare.net

Domain Information

yarnpkg.com

Domain Age

9y 4m

Created

22.09.2016

Expires

22.09.2027

Last Updated

26.11.2025

Registrar

Cloudflare, Inc.

DNSSEC

Not Enabled

Typography & Readability

PT Sans

68/100

Readability

/30

40/40

16px · LH 1.65

Hierarchy

/20

25/25

4x ratio

WCAG

/25

5/15

Contrast: undefined

Performance

/25

13/20

1 font

Heading Font

PT Sans

Sans64px

Body Font

PT Sans

Sans16px

Contrast Ratio

Reading Comfort

~39 CPL

Needs attention

64px

20px

16px

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

✅ Optimal line spacing: 1.65 ratio ensures comfortable reading.

✅ Strong hierarchy: Headlines are 4.0x larger than 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.

✅ Smart font loading: Using font-display: swap prevents invisible text during load.

Buy on MyFonts

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)datadoghq-browser-agent.com(1)

Website Identity

GitHub Discord

Sponsored

Last analyzed: 13 Feb 2026 at 19:34

Historical Analysis & Change Tracking