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

Affirm vs Klarna

Side-by-side comparison based on real-world adoption data from 53 detections across analyzed websites.

Market Share Distribution

Affirm (51%)Klarna (49%)

Total Detections

Affirm

HIGHER

Klarna

Websites Using

Affirm

HIGHER

Klarna

Used Together

websites use both

2% OVERLAP

Affirm

Payment

Affirm is a loan company that allows users to buy goods or services offered by online merchants and pay off those purchases in fixed monthly payments.

27 detections

27 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

Affirm has a slight edge over Klarna, detected on 27 vs 26 websites. 1 website uses both technologies together (2% overlap). Both are in the Payment category, making them direct alternatives.

Frequently Asked Questions

What is the difference between Affirm and Klarna?

Affirm is a loan company that allows users to buy goods or services offered by online merchants and pay off those purchases in fixed monthly payments. 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, Affirm or Klarna?

Based on our analysis of real websites, Affirm is more widely adopted with 27 detections compared to Klarna's 26.

Can Affirm and Klarna be used together?

Yes! We've detected 1 website that use both Affirm and Klarna together, showing they can complement each other in certain setups.

Check Any Website's Technology Stack

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

Analyze a Website

More Comparisons

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Affirm vs Klarna

Market Share Distribution

Affirm

Klarna

Our Analysis

Sites Using Both (1)

Only Affirm

Only Klarna

Frequently Asked Questions

What is the difference between Affirm and Klarna?

Which is more popular, Affirm or Klarna?

Can Affirm and Klarna be used together?

Check Any Website's Technology Stack

More Comparisons