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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pdffiller.com

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

Export

pdffiller.com

Mobile

Sponsored

Hosting Provider

Amazon Web Services (AWS)

aws.amazon.com

IP Address

52.71.186.180

Server Location

🇺🇸 Ashburn, United States

ASN

AS14618

Organization

AWS EC2 (us-east-1)

Server

Nginx

Nameservers

ns-1872.awsdns-42.co.uk.ns-663.awsdns-18.net.ns-93.awsdns-11.com.ns-1479.awsdns-56.org.

Performance

Page Speed

8 KB

90 requests

Image Optimization

Lazy LoadWebP

0–49

50–89

90–100

Architecture Stack

Monolithic

⚙️ SSR

Infrastructure

Hosting

Amazon Web Services (AWS)

Technology Stack

12 Technologies Detected

Analytics

Google Analytics

Google Analytics 4

Advertising

Google Ads Microsoft Advertising

Libraries

Other

CSS Frameworks

Fonts

Tag Managers

Other

Reviews

Web Servers

SEO Analysis

A88/100

pdffiller.compdffiller.com

pdfFiller: All-in-One PDF Editing & Document Management Solution

Edit, create, and manage PDFs online with pdfFiller. Streamline workflows with seamless eSignatures, unlimited cloud storage, and extensive form libraries.

Title Length64 chars

Recommended: 50-60 chars

Description Length155 chars

Recommended: 120-160 chars

Issues (0)

2 issues found

Upgrade to view details

Crawlability

Sitemap

Type: index

219 URLs

robots.txt

56 rules

Sitemap reference found

Sponsored

Security Score

56%Poor

Interactive

HTTPS

No WAF

76d

Certificate Details

Type

Organization Validated (OV)

Certificate Authority

DigiCert Inc

Key Algorithm

ECDSA (secp256r1) (256 bit)

Signature

ECDSA with SHA-384

TLS Version

TLSv1.3

HTTP Protocol

HTTP/2

Valid From

05.05.2025

Valid Until

06.05.2026

OCSP Stapling

Enabled

Subject Alternative Names (2)

*.pdffiller.compdffiller.com

SHA-256 Fingerprint

06:F5:83:E0:39:22:2A:1F:E9:E5:D4:B5:72:EE:D0:37:A0:13:9E:F8...

Top Recommendations

Security recommendation preview

Upgrade to view recommendations

Upgrade to view header details

HTTP Headers

Developer Console

cache-control

🔴 No Cache(private, no-cache, no-store, must-revalidate)

content-encoding

📦 Gzip(gzip)

content-security-policy-report-only

frame-ancestors 'self' *.pdffiller.com *.signnow.com *.airsl...

content-type

text/html; charset=UTF-8

date

Thu, 19 Feb 2026 21:05:08 GMT

expires

Thu, 19 Feb 2026 21:05:08 GMT

Good Warning Issue

Email Infrastructure

Google Workspace

Score

100

SPF

DKIM

DMARC

DMARC Policy

Reject (Strictest)

MX Records (5)

alt1.aspmx.l.google.com

aspmx3.googlemail.com

alt2.aspmx.l.google.com

aspmx2.googlemail.com

+1 more

Domain Information

pdffiller.com

Domain Age

19 years

Created

02.02.2007

Expires

02.02.2027

Last Updated

03.02.2026

Registrar

GoDaddy.com, LLC

DNSSEC

Not Enabled

Privacy & Compliance

Cookie Consent Banner

GDPR Indicators

Data Protection Officer mentioned

Typography & Readability

Open Sans

80/100

Readability

/30

32/40

24px · LH 1.33

Hierarchy

/20

25/25

2.5x ratio

WCAG

/25

15/15

Contrast: undefined

Performance

/25

13/20

2 fonts

Heading Font

Open Sans

Sans60px

Body Font

Open Sans

Sans24px

Contrast Ratio

Reading Comfort

Single Font Family

left aligned

60px

48px

44px

24px

✅ Excellent readability: 24px body text is ideal for all devices.

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

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

✅ Consistent design: Single font family with weight variations is a modern best practice.

⚠️ Cramped layout: 7 elements lack adequate spacing.

✅ Clean layout: Consistent left alignment throughout.

Buy on MyFonts

Business & Marketing Stack

6 Tools Detected

Enterprise

Behavior Analytics

Google Tag ManagerFree

Google AnalyticsFree

User behavior and product analytics

Advertising

Microsoft AdsEnterprise

Google AdsEnterprise

Quora PixelMid-Market

Ad platforms and retargeting pixels

Privacy & Cookies

Quantcast ChoiceMid-Market

Cookie consent and privacy compliance tools

Sponsored

Scripts & Styles

29 Resources

Scripts

Styles

Async

Defer

Top Script Sources

mkt-cf.pdffiller.com(5)bat.bing.com(4)cdn.privacy-mgmt.com(4)googletagmanager.com(3)upsellit.com(1)

Website Identity

Facebook X (Twitter)Instagram LinkedIn

Sponsored

Last analyzed: 19 Feb 2026 at 21:05

Historical Analysis & Change Tracking