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

letsencrypt.org

https://letsencrypt.org· First analyzed 10 Feb 2026· Updated 10 Feb 2026

Export

letsencrypt.org

Mobile

Sponsored

Hosting Provider

Amazon Web Services (AWS)

aws.amazon.com

IP Address

35.157.26.135

Server Location

🇩🇪 Frankfurt am Main, Germany

ASN

AS16509

Organization

AWS EC2 (eu-central-1)

Server

Netlify

CDN

Cloudflare

WAF

Cloudflare

Nameservers

owen.ns.cloudflare.com.vera.ns.cloudflare.com.

Performance

Page Speed

873 KB

22 requests

0–49

50–89

90–100

Architecture Stack

Monolithic

⚙️ SSR

Frontend

Styling

Tailwind CSS

CMS

Jimdo

Infrastructure

Hosting

Amazon Web Services (AWS)

CDN

Cloudflare

Technology Stack

4 Technologies Detected

CSS Frameworks

Icon Libraries

Customer Support

Platforms

SEO Analysis

D58/100

letsencrypt.orgletsencrypt.org

Let's Encrypt

Let's Encrypt is a free, automated, and open Certificate Authority brought to you by the nonprofit Internet Security Research Group (ISRG). Read all about ou...

Description truncated.

Title Length13 chars

Recommended: 50-60 chars

Description Length211 chars

Recommended: 120-160 chars

Issues (0)

6 issues found

Upgrade to view details

Sponsored

A+

Security Score

100%Excellent

Static / Informational

HTTPS

No WAF

55d

Upgrade to view header details

HTTP Headers

Developer Console

accept-ranges

bytes

age

37216

cache-control

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

cache-status

"Netlify Edge"; hit

content-encoding

⚡ Brotli(br)

content-length

9282

Good Warning Issue

Typography & Readability

ui-sans-serif

89/100

Readability

/30

32/40

14px · LH 1.43

Hierarchy

/20

25/25

4.29x ratio

WCAG

/25

15/15

Contrast: undefined

Performance

/25

20/20

System fonts

Heading Font

ui-sans-serif

Sans60px

Body Font

ui-sans-serif

Sans14px

Contrast Ratio

Reading Comfort

~35 CPL

Needs attention

60px

30px

20px

14px

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

✅ Optimal line spacing: 1.43 ratio ensures comfortable reading.

✅ Strong hierarchy: Headlines are 4.3x larger than body text.

✅ 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.

Business & Marketing Stack

1 Tools Detected

Growing

Behavior Analytics

Google AnalyticsFree

User behavior and product analytics

Sponsored

Scripts & Styles

8 Resources

Scripts

Styles

Async

Defer

Top Script Sources

local(6)

Sponsored

Last analyzed: 10 Feb 2026 at 23:23

Historical Analysis & Change Tracking