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.

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flattr.com

https://flattr.com· First analyzed 19 Feb 2026· Updated 19 Feb 2026

Export

flattr.com

Mobile

Sponsored

Hosting Provider

Google Cloud Platform

cloud.google.com

IP Address

199.36.158.100

Server Location

🇺🇸 Mountain View, United States

ASN

AS54113

Organization

Google LLC

Server

Google Frontend

CDN

Fastly

Nameservers

pdns73.ultradns.co.uk.pdns73.ultradns.biz.pdns73.ultradns.com.pdns73.ultradns.net.+2 more

Performance

Page Speed

94 KB

12 requests

0–49

50–89

90–100

Architecture Stack

Monolithic

⚙️ SSR

Infrastructure

Hosting

Google Cloud Platform

CDN

Fastly

Progressive Web App

Web ManifestApple Touch IconTheme Color

Technology Stack

4 Technologies Detected

Frameworks

Svelte

Meta Frameworks

SvelteKit

CSS Frameworks

Tailwind CSS

Languages

SEO Analysis

C64/100

flattr.comflattr.com

404 | Service No Longer Exists

(╯°□°）╯︵ ┻━┻

Title Length30 chars

Recommended: 50-60 chars

Description Length12 chars

Recommended: 120-160 chars

Issues (0)

3 issues found

Upgrade to view details

Sponsored

Security Score

76%Good

Static / Informational

HTTPS

No WAF

83d

Certificate Details

Type

Domain Validated (DV)

Certificate Authority

Google Trust Services

Key Algorithm

RSA (2048 bit)

Signature

SHA-256 with RSA

TLS Version

TLSv1.3

HTTP Protocol

HTTP/2+H3

Valid From

13.02.2026

Valid Until

14.05.2026

OCSP Stapling

Enabled

Subject Alternative Names (2)

flattr.comwww.flattr.com

SHA-256 Fingerprint

93:F2:1E:3B:8C:23:F3:18:80:6F:20:3A:23:32:AB:49:1A:9A:F1:76...

Recommendations

Security recommendation preview

Upgrade to view recommendations

Upgrade to view header details

HTTP Headers

Developer Console

accept-ranges

bytes

alt-svc

h3=":443";ma=86400,h3-29=":443";ma=86400,h3-27=":443";ma=864...

cache-control

🟣 Private(private)

content-length

7325

content-type

text/html

date

Thu, 19 Feb 2026 21:17:51 GMT

Good Warning Issue

Email Infrastructure

Google Workspace

Score

SPF

DKIM

DMARC

MX Records (1)

smtp.google.com

Domain Information

flattr.com

Domain Age

18y 10m

Created

05.04.2007

Expires

05.04.2026

Last Updated

23.11.2025

Registrar

RegistryGate GmbH

DNSSEC

Not Enabled

Typography & Readability

Poppins + ui-monospace

85/100

Readability

/30

40/40

16px · LH 1.75

Hierarchy

/20

18/25

2.49x ratio

WCAG

/25

12/15

Contrast: undefined

Performance

/25

17/20

System fonts

Heading Font

Poppins

Sans40px

Body Font

ui-monospace

Mono16px

Contrast Ratio

Reading Comfort

~32 CPL

Needs attention

40px

28px

16px

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

✅ Optimal line spacing: 1.75 ratio ensures comfortable reading.

✅ Strong hierarchy: Headlines are 2.5x larger than body text.

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

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

Buy on MyFonts

Business & Marketing Stack

1 Tools Detected

Growing

Behavior Analytics

Google AnalyticsFree

User behavior and product analytics

Sponsored

Scripts & Styles

1 Resources

Scripts

Styles

Async

Defer

Top Script Sources

Sponsored

Last analyzed: 19 Feb 2026 at 21:17

Historical Analysis & Change Tracking