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

yjtag.jp

https://yjtag.jp· First analyzed 18 Feb 2026· Updated 18 Feb 2026

Export

yjtag.jp

Sponsored

Hosting Provider

YAHOO

IP Address

202.239.2.248

Server Location

🇯🇵 Chiyoda City, Japan

ASN

AS23816

Organization

YAHOO

Nameservers

ns01.yahoo.co.jp.ns02.yahoo.co.jp.ns12.yahoo.co.jp.ns11.yahoo.co.jp.

Performance

Page Speed

6 requests

0–49

50–89

90–100

Architecture Stack

Monolithic

⚙️ SSR

Infrastructure

Hosting

YAHOO

SEO Analysis

D41/100

yjtag.jpyjtag.jp

【お知らせ】欧州経済領域（EEA）およびイギリスからご利用のお客様へ - Yahoo! JAPAN

No description available for this page.

Title Length49 chars

Recommended: 50-60 chars

Description Length0 chars

Recommended: 120-160 chars

Issues (2)

• Missing meta description - important for click-through rates
• Missing H1 tag - every page should have one H1

6 issues found

Upgrade to view details

Sponsored

Security Score

86%Very Good

Static / Informational

HTTPS

No WAF

354d

Certificate Details

Type

Organization Validated (OV)

Certificate Authority

Cybertrust Japan Co., Ltd.

Key Algorithm

RSA (2048 bit)

Signature

SHA-256 with RSA

TLS Version

TLSv1.2

HTTP Protocol

HTTP/2

Valid From

08.01.2026

Valid Until

07.02.2027

OCSP Stapling

Enabled

Subject Alternative Names (20)

gw01.yahoo.co.jp*.yahoo.co.jp*.yahooapis.jp*.yimg.jp*.c.yimg.jp*.edge.storage-yahoo.jp*.east.edge.storage-yahoo.jp*.west.edge.storage-yahoo.jp+12 more

SHA-256 Fingerprint

67:73:73:16:3B:2F:F6:00:F2:3B:34:AC:85:EF:FC:03:41:2B:AA:62...

Recommendations

Security recommendation preview

Upgrade to view recommendations

Upgrade to view header details

HTTP Headers

Developer Console

content-length

10052

content-type

text/html

date

Wed, 18 Feb 2026 06:38:59 GMT

x-content-type-options

nosniff

x-frame-options

SAMEORIGIN

x-xss-protection

1; mode=block

Good Warning Issue

Email Infrastructure

Custom Mail Server

Score

SPF

DKIM

DMARC

Domain Information

yjtag.jp

DNSSEC

Not Enabled

Privacy & Compliance

Cookie Consent Banner

GDPR Indicators

Typography & Readability

-apple-system

80/100

Readability

/30

40/40

16px · LH 1.70

Hierarchy

/20

8/25

WCAG

/25

15/15

Contrast: undefined

Performance

/25

20/20

System fonts

Heading Font

-apple-system

Sans

Body Font

-apple-system

Sans16px

Contrast Ratio

Reading Comfort

~41 CPL

Needs attention

24px

32px

16px

Perfect Fourth

Scale

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

✅ Optimal line spacing: 1.70 ratio ensures comfortable reading.

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

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

✅ Clean layout: Consistent left alignment throughout.

Sponsored

Scripts & Styles

5 Resources

Scripts

Styles

Async

Defer

Top Script Sources

Sponsored

Last analyzed: 18 Feb 2026 at 06:39

Historical Analysis & Change Tracking