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

semver.org

https://semver.org· First analyzed 14 Feb 2026· Updated 14 Feb 2026

Export

semver.org

Mobile

Sponsored

Hosting Provider

GitHub Pages

pages.github.com

IP Address

185.199.111.153

Server Location

🇺🇸 San Francisco, United States

ASN

AS54113

Organization

GitHub, Inc

Server

GitHub.com

CDN

Fastly

Nameservers

ns4.dnsimple-edge.org.ns1.dnsimple.com.ns2.dnsimple-edge.net.ns3.dnsimple.com.

Performance

Page Speed

3 KB

2 requests

0–49

50–89

90–100

Architecture Stack

Monolithic

⚙️ SSR

Infrastructure

Hosting

GitHub Pages

CDN

Fastly

Technology Stack

1 Technologies Detected

CSS Frameworks

Tailwind CSS

SEO Analysis

A84/100

semver.orgsemver.org

Semantic Versioning 2.0.0 | Semantic Versioning

Semantic Versioning spec and website

Title Length47 chars

Recommended: 50-60 chars

Description Length36 chars

Recommended: 120-160 chars

Issues (0)

1 issues found

Upgrade to view details

Crawlability

Sitemap

Type: standard

98 URLs

robots.txt

1 rules

Sitemap reference found

Allows all crawlers

Sponsored

Security Score

71%Good

Static / Informational

HTTPS

No WAF

34d

Certificate Details

Type

Domain Validated (DV)

Certificate Authority

Let's Encrypt

Key Algorithm

RSA (2048 bit)

Signature

SHA-256 with RSA

TLS Version

TLSv1.3

HTTP Protocol

HTTP/2

Valid From

20.12.2025

Valid Until

20.03.2026

Subject Alternative Names (2)

semver.orgwww.semver.org

SHA-256 Fingerprint

8C:F5:C1:7F:38:6F:09:7A:DD:F3:9C:7E:58:2C:90:35:29:A7:2F:0F...

Recommendations

Security recommendation preview

Upgrade to view recommendations

Upgrade to view header details

HTTP Headers

Developer Console

accept-ranges

bytes

access-control-allow-origin

age

cache-control

🟡 600s(max-age=600)

content-encoding

📦 Gzip(gzip)

content-length

9073

Good Warning Issue

Email Infrastructure

Custom Mail Server

Score

SPF

DKIM

DMARC

Domain Information

semver.org

Domain Age

16y 2m

Created

14.12.2009

Expires

14.12.2029

Last Updated

20.11.2025

Registrar

1API GmbH

DNSSEC

Not Enabled

Typography & Readability

Helvetica

78/100

Readability

/30

32/40

14px · LH 1.50

Hierarchy

/20

25/25

2.99x ratio

WCAG

/25

15/15

Contrast: undefined

Performance

/25

13/20

1 font

Heading Font

Helvetica

Sans43px

Body Font

Helvetica

Sans14px

Contrast Ratio

Reading Comfort

~37 CPL

Needs attention

43px

24px

16px

14px

⚠️ Small text: 14px may be hard to read on mobile. Consider 16px+.

✅ Optimal line spacing: 1.50 ratio ensures comfortable reading.

✅ Strong hierarchy: Headlines are 3.0x 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.

⚠️ Cramped layout: 6 elements lack adequate spacing.

Buy on MyFonts

Business & Marketing Stack

1 Tools Detected

Growing

Behavior Analytics

Google AnalyticsFree

User behavior and product analytics

Sponsored

Scripts & Styles

2 Resources

Scripts

Styles

Async

Defer

Top Script Sources

local(1)

Website Identity

GitHub

Sponsored

Last analyzed: 14 Feb 2026 at 06:08

Historical Analysis & Change Tracking