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

4.cn

https://4.cn· First analyzed 13 Feb 2026· Updated 13 Feb 2026

Export

4.cn

Mobile

Sponsored

Hosting Provider

Amazon Web Services (AWS)

aws.amazon.com

IP Address

69.234.239.50

Server Location

🇨🇳 Yinchuan, China

ASN

AS135629

Organization

AWS EC2 (cn-northwest-1)

Server

Nginx

Nameservers

vip3.alidns.com.vip4.alidns.com.

Performance

Page Speed

242 KB

50 requests

0–49

50–89

90–100

Architecture Stack

Monolithic

⚙️ SSR

Infrastructure

Hosting

Amazon Web Services (AWS)

Technology Stack

7 Technologies Detected

Analytics

Libraries

CSS Frameworks

Web Servers

Languages

Customer Support

SEO Analysis

D50/100

4.cn4.cn

4.CN - Buy, Sell & Park Domain Names

4.CN is the global and professional marketplace for buying and selling domain names. We have over 1.500.000 domains in our marketplace. Currently we are the ...

Description truncated.

Title Length36 chars

Recommended: 50-60 chars

Description Length237 chars

Recommended: 120-160 chars

Issues (2)

• Many images missing alt text (12/13)
• Missing viewport meta tag - page may not be mobile-friendly

7 issues found

Upgrade to view details

Crawlability

Sitemap

robots.txt

2 rules

Allows all crawlers

Sponsored

Security Score

0%Critical

Critical / Transactional

HTTPS

No WAF

50d

Certificate Details

Type

Domain Validated (DV)

Certificate Authority

Let's Encrypt

Key Algorithm

RSA (2048 bit)

Signature

SHA-256 with RSA

TLS Version

TLSv1.2

HTTP Protocol

HTTP/2

Valid From

05.01.2026

Valid Until

05.04.2026

Subject Alternative Names (2)

*.4.cn4.cn

SHA-256 Fingerprint

30:35:6D:E8:42:08:21:A2:51:5C:EC:33:CB:56:EC:E4:09:F6:FD:A3...

Top Recommendations

Security recommendation preview

Upgrade to view recommendations

Upgrade to view header details

HTTP Headers

Developer Console

cache-control

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

content-encoding

📦 Gzip(gzip)

content-type

text/html; charset=UTF-8

date

Fri, 13 Feb 2026 08:36:56 GMT

expires

Thu, 19 Nov 1981 08:52:00 GMT

pragma

no-cache

Good Warning Issue

Email Infrastructure

Custom Mail Server

Score

SPF

DKIM

DMARC

DMARC Policy

Quarantine (Moderate)

MX Records (1)

mail.tutanota.de

Domain Information

4.cn

DNSSEC

Not Enabled

Privacy & Compliance

Cookie Consent Banner

Typography & Readability

Arial

28/100

Readability

/30

10/40

12px · LH --

Hierarchy

/20

8/25

1x ratio

WCAG

/25

5/15

Contrast: undefined

Performance

/25

20/20

System fonts

Heading Font

Arial

Sans12px

Body Font

Arial

Sans12px

Contrast Ratio

Reading Comfort

~41 CPL

Needs attention

12px

Minor Second

Scale

❌ Critical: 12px body text is too small. Increase to at least 14px.

⚠️ Weak hierarchy: Headlines should be at least 2x body size for clear visual structure.

✅ Excellent performance: System fonts eliminate font loading delays (better LCP).

✅ Consistent design: Single font family with weight variations is a modern best practice.

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

⚠️ Cramped layout: 20 elements lack adequate spacing.

Business & Marketing Stack

1 Tools Detected

Growing

Behavior Analytics

Google AnalyticsFree

User behavior and product analytics

Sponsored

Scripts & Styles

17 Resources

Scripts

Styles

Async

Defer

Top Script Sources

local(10)google-analytics.com(1)s141.cnzz.com(1)

Website Identity

4.cn

Social Profiles

Facebook X (Twitter)Telegram

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Last analyzed: 13 Feb 2026 at 08:37

Historical Analysis & Change Tracking