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

nixos.org

https://nixos.org· First analyzed 20 Feb 2026· Updated 20 Feb 2026

Export

nixos.org

Sponsored

Hosting Provider

Amazon Web Services (AWS)

aws.amazon.com

IP Address

75.2.60.5

Server Location

🇺🇸 Seattle, United States

ASN

AS16509

Organization

AWS Global Accelerator (GLOBAL)

Server

Netlify

Nameservers

ns-161-c.gandi.net.ns-61-b.gandi.net.ns-177-a.gandi.net.

Performance

Page Speed

430 KB

18 requests

Image Optimization

Lazy Load

0–49

50–89

90–100

Architecture Stack

Hybrid

⚙️ SSR

Frontend

Framework

Astro

Styling

Tailwind CSS

Infrastructure

Hosting

Amazon Web Services (AWS)

Progressive Web App

Web ManifestApple Touch IconTheme Color

Technology Stack

3 Technologies Detected

Meta Frameworks

Astro

CSS Frameworks

Tailwind CSS

Platforms

Netlify

SEO Analysis

A80/100

nixos.orgnixos.org

Nix & NixOS | Declarative builds and deployments

Nix is a tool that takes a unique approach to package management and system configuration. Learn how to make reproducible, declarative and reliable systems.

Title Length48 chars

Recommended: 50-60 chars

Description Length156 chars

Recommended: 120-160 chars

Issues (0)

3 issues found

Upgrade to view details

Crawlability

Sitemap

Type: index

1 URLs

robots.txt

3 rules

Sitemap reference found

Allows all crawlers

Sponsored

Security Score

36%Critical

Interactive

HTTPS

No WAF

44d

Certificate Details

Type

Domain Validated (DV)

Certificate Authority

Let's Encrypt

Key Algorithm

ECDSA (secp256r1) (256 bit)

Signature

ECDSA with SHA-384

TLS Version

TLSv1.3

HTTP Protocol

HTTP/2

Valid From

05.01.2026

Valid Until

05.04.2026

Subject Alternative Names (2)

nixos.orgwww.nixos.org

SHA-256 Fingerprint

B0:9B:99:2A:0E:26:27:E3:37:76:F1:CF:81:6A:FD:5A:B3:F6:2F:49...

Top Recommendations

Security recommendation preview

Upgrade to view recommendations

Upgrade to view header details

HTTP Headers

Developer Console

accept-ranges

bytes

age

17087

cache-control

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

cache-status

"Netlify Edge"; hit

content-encoding

⚡ Brotli(br)

content-length

12131

Good Warning Issue

Email Infrastructure

Custom Mail Server

Score

SPF

DKIM

DMARC

DMARC Policy

None (Monitor Only)

MX Records (1)

umbriel.nixos.org

Domain Information

nixos.org

Domain Age

18y 11m

Created

17.03.2007

Expires

17.03.2027

Last Updated

21.01.2026

Registrar

Gandi SAS

DNSSEC

Not Enabled

Privacy & Compliance

Cookie Consent Banner

GDPR Indicators

Typography & Readability

Overpass Variable + Roboto Flex Variable

58/100

Readability

/30

32/40

22px · LH 2.00

Hierarchy

/20

25/25

2.18x ratio

WCAG

/25

5/15

Contrast: undefined

Performance

/25

13/20

2 fonts

Heading Font

Overpass Variable

Sans49px

Body Font

Roboto Flex Variable

Sans22px

Contrast Ratio

Reading Comfort

~39 CPL

Needs attention

49px

31px

22px

16px

22px

✅ Excellent readability: 22px body text is ideal for all devices.

✅ Strong hierarchy: Headlines are 2.2x larger than body text.

✅ Good performance: Using 2 font families keeps load times fast.

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

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

⚠️ Cramped layout: 26 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

5 Resources

Scripts

Styles

Async

Defer

Top Script Sources

local(2)

Website Identity

X (Twitter)YouTube GitHub

Sponsored

Last analyzed: 20 Feb 2026 at 01:39

Historical Analysis & Change Tracking