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.

Technology Comparison

Afterpay vs Klarna

Side-by-side comparison based on real-world adoption data from 29 detections across analyzed websites.

Market Share Distribution

Afterpay (10%)Klarna (90%)

Total Detections

Afterpay

Klarna

HIGHER

Websites Using

Afterpay

Klarna

HIGHER

Used Together

websites use both

Afterpay

Payment

Afterpay is a 'buy now, pay later' platform that makes it possible to pay off purchased goods in fortnightly instalments.

3 detections

3 sites

Visit Website View Profile

Klarna

Payment

Klarna is a Swedish fintech company that provides financial services such as payments for online storefronts and direct payments. It offers a flexible payment solution for consumers, allowing them to pay now, pay later, or pay in installments.

26 detections

26 sites

Visit Website View Profile

Our Analysis

Klarna is significantly more popular than Afterpay in our dataset, appearing on 26 websites compared to 3. Both are in the Payment category, making them direct alternatives.

Sites Using Both (0)

No sites use both technologies together.

Only Afterpay

asics.com trademe.co.nz victoriassecret.com

Only Klarna

adf.ly atariden.com balenciaga.com barternewsweekly.com belkin.com bodybuilding.com columbia.com dfb.de dolcegabbana.com ecoflow.com

Frequently Asked Questions

What is the difference between Afterpay and Klarna?

Afterpay is a 'buy now, pay later' platform that makes it possible to pay off purchased goods in fortnightly instalments. Klarna is a Swedish fintech company that provides financial services such as payments for online storefronts and direct payments. It offers a flexible payment solution for consumers, allowing them to pay now, pay later, or pay in installments. Both belong to the Payment category, making them direct alternatives.

Which is more popular, Afterpay or Klarna?

Based on our analysis of real websites, Klarna is more widely adopted with 26 detections compared to Afterpay's 3.

Can Afterpay and Klarna be used together?

In our current dataset, no websites use both technologies simultaneously. This suggests they typically serve as alternatives rather than complementary tools.

Check Any Website's Technology Stack

Find out if a website uses Afterpay, Klarna, or any other technology.

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