StackPeek vs WhatCMS: Full Tech Stack Detection vs CMS-Only Identification

If you are evaluating technology detection APIs, you have probably come across WhatCMS. It is a popular choice for identifying content management systems—WordPress, Shopify, Joomla, and the like. But CMS detection is only one piece of the puzzle. Modern websites run dozens of technologies across frameworks, analytics, CDNs, payment processors, and authentication providers. This post breaks down exactly where WhatCMS ends and StackPeek begins, with real API comparisons, pricing tables, and code examples so you can make the right call for your use case.

1. What WhatCMS Does (and Does Not Do)

WhatCMS is a focused tool built for one job: identifying the content management system behind a website. Give it a URL, and it tells you whether the site runs WordPress, Shopify, Squarespace, Drupal, Ghost, or one of several hundred other CMS platforms. It does this well, and it has been a reliable option for years.

Here is what WhatCMS returns in a typical API response:

{
  "result": {
    "code": 200,
    "msg": "CMS Found"
  },
  "results": [
    {
      "name": "WordPress",
      "version": "6.4",
      "confidence": 99
    }
  ]
}

That is the entire response. You get the CMS name, an optional version number, and a confidence score. No analytics tools. No CDN provider. No JavaScript framework. No payment processor. No fonts, no hosting provider, no security headers.

For teams that genuinely only need CMS identification—for example, an agency qualifying inbound leads by platform—this is perfectly fine. But the moment you need to understand what else a site is running, WhatCMS cannot help you. That is where the two tools diverge.

2. What StackPeek Does: Full-Stack Detection

StackPeek takes a fundamentally different approach. Instead of asking “what CMS is this?” it asks “what is everything this website is built with?” A single API call returns every detectable technology across 15 categories using 120+ fingerprints.

Those 15 categories include:

• CMS — WordPress, Shopify, Ghost, Webflow, Squarespace
• Frameworks — React, Vue, Angular, Next.js, Nuxt, Svelte
• Analytics — Google Analytics, Mixpanel, Segment, Hotjar, Plausible
• CDN — Cloudflare, Fastly, AWS CloudFront, Akamai
• Payment processors — Stripe, PayPal, Square, Braintree
• Authentication — Auth0, Firebase Auth, Okta, Clerk
• Hosting — Vercel, Netlify, AWS, Google Cloud, Heroku
• Fonts — Google Fonts, Adobe Fonts, custom web fonts
• Tag managers — Google Tag Manager, Segment, Tealium
• Advertising — Google Ads, Facebook Pixel, LinkedIn Insight
• Security — HSTS, CSP headers, X-Frame-Options, SSL providers
• JavaScript libraries — jQuery, Lodash, Moment.js, GSAP
• Build tools — Webpack, Vite, Parcel, esbuild
• Chat & support — Intercom, Drift, Zendesk, Crisp
• Email marketing — Mailchimp, ConvertKit, SendGrid embeds

Every detected technology includes a confidence score from 0 to 100, so you can programmatically filter results and only act on high-confidence detections.

3. Feature Comparison Table

Here is how the two tools compare across the features that matter most for developers and sales teams:

The pattern is clear. WhatCMS goes deep on CMS identification with a large database of CMS platforms. StackPeek goes wide across the entire technology stack. If CMS is all you need, WhatCMS works. If you need the full picture, StackPeek is the only choice that does not require stitching together multiple APIs.

4. Pricing Comparison

Both tools use tiered pricing based on the number of API calls per month. Here is a side-by-side breakdown:

At the Starter tier, StackPeek gives you 2.5x more detections for $1 less. At Pro tier, you get 25,000 detections for $29 compared to WhatCMS’s 10,000 for $25—that is 2.5x more detections for only $4 more, and each detection returns the full technology stack instead of just the CMS. At Business tier, WhatCMS charges $50/month for 20,000 CMS-only detections, while StackPeek’s Pro plan already gives you 25,000 full-stack detections for $29.

Put differently: the cost per detection on StackPeek is $0.00116 at Pro versus WhatCMS’s $0.0025 at their Business tier. That is more than double the cost for a fraction of the data.

5. Real API Response Comparison

The best way to understand the difference is to see what each API actually returns for the same URL. Let us scan https://linear.app with both tools.

WhatCMS Response

curl "https://whatcms.org/API/Tech?key=YOUR_KEY&url=https://linear.app"

{
  "result": {
    "code": 200,
    "msg": "CMS Not Found"
  },
  "results": []
}

WhatCMS returns nothing. Linear.app is a custom-built SaaS application—it does not use a traditional CMS. So WhatCMS draws a blank. Zero useful data.

StackPeek Response

curl "https://us-central1-todd-agent-prod.cloudfunctions.net/stackpeekApi/api/v1/detect?url=https://linear.app"

{
  "url": "https://linear.app",
  "technologies": [
    {"name": "React", "category": "framework", "confidence": 95},
    {"name": "Next.js", "category": "framework", "confidence": 92},
    {"name": "Cloudflare", "category": "cdn", "confidence": 98},
    {"name": "Vercel", "category": "hosting", "confidence": 88},
    {"name": "Segment", "category": "analytics", "confidence": 85},
    {"name": "Google Fonts", "category": "fonts", "confidence": 100},
    {"name": "Stripe", "category": "payments", "confidence": 78},
    {"name": "HSTS", "category": "security", "confidence": 100},
    {"name": "Intercom", "category": "chat", "confidence": 90},
    {"name": "Webpack", "category": "build_tool", "confidence": 72}
  ],
  "categories_detected": 8,
  "total_technologies": 10,
  "scan_time_ms": 387
}

StackPeek returns 10 technologies across 8 categories in 387 milliseconds. You now know Linear uses React with Next.js, deploys on Vercel behind Cloudflare CDN, processes payments with Stripe, uses Intercom for customer chat, tracks analytics with Segment, and enforces strict transport security. From a single API call.

This is the core value proposition. WhatCMS sees nothing because there is no CMS. StackPeek sees everything because it fingerprints the entire stack.

Using StackPeek in Python

Here is a practical example for integrating StackPeek into your workflow:

import requests

STACKPEEK_API = "https://us-central1-todd-agent-prod.cloudfunctions.net/stackpeekApi/api/v1/detect"

def detect_stack(url: str) -> dict:
    """Detect the full technology stack of a URL."""
    response = requests.get(STACKPEEK_API, params={"url": url}, timeout=15)
    response.raise_for_status()
    return response.json()

result = detect_stack("https://linear.app")

# Group technologies by category
by_category = {}
for tech in result.get("technologies", []):
    cat = tech["category"]
    by_category.setdefault(cat, []).append(tech)

for category, techs in sorted(by_category.items()):
    print(f"\n{category.upper()}")
    for t in techs:
        print(f"  {t['name']} (confidence: {t['confidence']}%)")

Output:

ANALYTICS
  Segment (confidence: 85%)

BUILD_TOOL
  Webpack (confidence: 72%)

CDN
  Cloudflare (confidence: 98%)

CHAT
  Intercom (confidence: 90%)

FONTS
  Google Fonts (confidence: 100%)

FRAMEWORK
  React (confidence: 95%)
  Next.js (confidence: 92%)

HOSTING
  Vercel (confidence: 88%)

PAYMENTS
  Stripe (confidence: 78%)

SECURITY
  HSTS (confidence: 100%)

6. When to Use WhatCMS

WhatCMS is the right choice if all of the following are true:

• You only need to know which CMS a website is running
• You are building a tool that specifically targets CMS platforms (e.g., a WordPress plugin marketplace, a Shopify app directory)
• You do not need framework, analytics, CDN, or payment detection
• Your volume is under 2,000 detections per month (their $10 Basic plan)
• You need CMS version detection and that is the only version you care about

WhatCMS has been around for years and maintains a solid database of CMS platforms. If CMS identification is your only requirement, it is a reasonable tool for the job.

7. When to Use StackPeek

StackPeek is the right choice when you need more than CMS data. Specific use cases include:

• Sales prospecting: You are building lead lists and want to know which companies use Stripe, Intercom, or Segment—not just WordPress
• Competitive intelligence: You need to understand what frameworks, CDNs, and analytics tools your competitors use
• Security auditing: You want to check security headers (HSTS, CSP, X-Frame-Options) alongside the technology stack
• Agency workflows: You onboard new clients and need a full technology audit before quoting a project
• Market research: You are analyzing technology adoption across thousands of websites and need rich, structured data
• Developer tools: You are building something that reacts to the detected technology (e.g., a browser extension, a monitoring dashboard)

In all of these scenarios, knowing that a site uses WordPress is only 10% of the picture. You need to know the CDN, the analytics suite, the payment stack, the frontend framework, and the hosting provider. StackPeek delivers all of that in a single call.

8. StackPeek Advantages at a Glance

Here is a summary of why teams are switching from WhatCMS to StackPeek:

• Broader detection: 120+ fingerprints across 15 categories versus CMS-only identification
• Cheaper at scale: $0.00116 per detection at Pro tier versus $0.0025 per detection on WhatCMS Business
• Faster API: Sub-500ms average response time versus 1–3 seconds on WhatCMS
• Confidence scores on everything: Every detected technology gets a 0–100 confidence score, not just the CMS
• Batch scanning: Scan up to 100 URLs in a single request, reducing overhead for bulk workflows
• Generous free tier: 100 detections per day versus WhatCMS’s 10 per day—10x more room to evaluate and prototype
• No API key for free tier: Start integrating immediately without signing up for an account
• Works on non-CMS sites: Custom SaaS apps, SPAs, and static sites that WhatCMS returns nothing for

The only area where WhatCMS has a genuine advantage is the depth of its CMS database. If you need to distinguish between obscure CMS platforms—say, Kentico versus Sitecore versus Adobe Experience Manager—WhatCMS may have broader CMS-specific coverage. For everything else, StackPeek delivers more data, faster, at a lower cost.

Part of the Peek Suite

StackPeek is one product in the Peek Suite—a collection of developer-focused APIs built for speed and simplicity. The suite also includes OGPeek for Open Graph preview generation, SEOPeek for instant SEO audits, and CronPeek for uptime monitoring. All products share the same design philosophy: one API call, fast JSON response, generous free tier, no bloat.

Frequently Asked Questions

What is the main difference between StackPeek and WhatCMS?

WhatCMS focuses exclusively on CMS detection—identifying whether a site uses WordPress, Shopify, Drupal, and similar platforms. StackPeek detects the full technology stack including JavaScript frameworks, CDN providers, analytics tools, payment processors, authentication services, fonts, security headers, and more across 15 categories with 120+ fingerprints. If you need more than CMS data, StackPeek is the more complete solution.

Is StackPeek cheaper than WhatCMS?

Yes, at every comparable tier. StackPeek’s Starter plan ($9/month) includes 5,000 detections versus WhatCMS Basic ($10/month) with 2,000 detections. At Pro level, StackPeek gives you 25,000 full-stack detections for $29/month, while WhatCMS charges $50/month for only 20,000 CMS-only detections at their Business tier. The free tier is also more generous: 100/day on StackPeek versus 10/day on WhatCMS.

Does WhatCMS detect JavaScript frameworks like React or Vue?

No. WhatCMS is limited to content management system identification. It cannot detect frontend frameworks (React, Vue, Angular, Svelte), analytics platforms (Google Analytics, Mixpanel), CDN providers (Cloudflare, Fastly), payment processors (Stripe, PayPal), or any of the other technology categories that StackPeek covers. If a website does not use a CMS, WhatCMS returns no results at all.

Does StackPeek provide confidence scores for detected technologies?

Yes. Every technology detected by StackPeek includes a confidence score from 0 to 100, indicating how certain the detection is based on the fingerprinting signals found. This helps you programmatically filter out low-confidence matches and focus on high-certainty results in your analysis, sales prospecting, or competitive intelligence workflows.

Can I migrate from WhatCMS to StackPeek without changing my code?

The API formats are different, so you will need to update your integration code. However, StackPeek’s API is a straightforward REST endpoint that returns JSON, and most teams complete the migration in under 30 minutes. The StackPeek response includes CMS data (matching what WhatCMS provides) plus all additional technology categories, so you get a strict superset of the data you had before—nothing is lost in the switch.