StackPeek vs SimilarTech vs WhatRuns: Which Tech Detection API Is Best in 2026?

Whether you're building a lead generation pipeline, running competitive analysis, or auditing web application security, you need reliable technology detection. The three names that keep coming up are SimilarTech, WhatRuns, and StackPeek. Each takes a fundamentally different approach to the same problem — and the right choice depends entirely on your use case and budget.

We'll break down exactly where each tool excels, where it falls short, and which one makes sense for your workflow in 2026.

Why Developers Need Tech Detection APIs

Programmatic technology detection has become a critical capability for three major workflows:

• Lead generation & sales intelligence: Sales teams filter prospects by tech stack — "show me every company running Shopify Plus" or "find all sites using HubSpot." This powers account-based marketing at scale.
• Competitive analysis: Product teams track what frameworks, CDNs, and analytics tools competitors adopt. Knowing a rival just migrated from Angular to Next.js tells you something about their roadmap.
• Security auditing: Penetration testers and DevSecOps teams enumerate exposed technologies to identify known vulnerabilities. Detecting an outdated jQuery version or misconfigured server header is step one of any audit.

The question isn't whether you need tech detection — it's which tool gives you the best data at a price that makes sense.

SimilarTech: Deep Historical Data, Enterprise Pricing

SimilarTech has been in the technology profiling space since 2014. Its core strength is historical technology adoption data — you can see when a website adopted or dropped a specific technology, track market share trends across millions of sites, and pull lead lists filtered by tech stack.

Strengths

• Historical data: Technology adoption timelines going back years, useful for market research and trend analysis
• Large database: Covers millions of websites with deep crawling infrastructure
• Lead list exports: Built-in tools for exporting company lists filtered by technology
• Market share reports: Aggregate data on technology adoption across industries

Weaknesses

• Expensive: API access starts at $299/month, with enterprise plans running significantly higher
• Slow responses: Lookups take 3–8 seconds due to heavy crawling infrastructure
• No free tier: No way to test the API without committing to a paid plan
• Overkill for real-time detection: If you just need to know what tech a site uses right now, SimilarTech's historical focus adds cost without adding value

SimilarTech is built for enterprise market research teams with budget to match. If you need historical trends and market share data, it delivers. If you need fast, affordable API lookups, you're paying for capabilities you won't use.

WhatRuns: Great Browser Extension, No API

WhatRuns is a popular Chrome and Firefox extension that identifies technologies on any page you visit. It's free, simple, and works well for manual, one-at-a-time lookups while browsing.

Strengths

• Free browser extension: Zero cost for casual use, installs in seconds
• Easy to use: Click the icon, see the tech stack. No configuration needed
• Decent detection: Identifies major frameworks, CMS platforms, and analytics tools

Weaknesses

• No API access: WhatRuns does not offer a public REST API. There is no way to programmatically query it.
• Browser-only: You must physically visit each page. Impossible to integrate into automated pipelines, CI/CD, or backend services.
• Limited detection depth: Detects fewer technologies than dedicated API services, particularly for server-side technologies, CDN configurations, and build tools
• No batch processing: Scanning 1,000 competitor URLs means clicking through 1,000 tabs

WhatRuns is a solid tool for the occasional manual check. But if you're searching for a "WhatRuns API alternative," you've already hit its ceiling. The moment you need automation, WhatRuns is out of the picture.

StackPeek: Fast, Affordable, API-First

StackPeek is built specifically for developers who need programmatic tech detection without enterprise pricing. It uses HTTP header analysis, HTML parsing, script fingerprinting, and meta tag detection to identify technologies in under 500ms — no headless browser required.

Strengths

• $9/month starter plan: 5,000 scans per month, making it 33x cheaper than SimilarTech
• Sub-500ms response times: Lightweight detection without headless browser overhead
• 120+ technology fingerprints: Covers frameworks, CMS, hosting, CDN, analytics, payments, and more across 15 categories
• Clean JSON API: Simple REST endpoint with confidence scores for every detection
• Free tier: 100 scans per day, no API key required

Weaknesses

• Smaller detection library: 120+ technologies vs SimilarTech's larger database. Niche plugins and obscure CMSes may not be covered.
• No historical data: StackPeek detects what a site uses right now. It doesn't track adoption history or market share trends.

StackPeek is purpose-built for the 90% use case: you have a URL, you want to know what it's built with, and you want the answer fast and cheap.

Feature Comparison Table

Which Should You Choose?

Choose StackPeek if you need:

• A fast, affordable API for real-time tech detection
• Integration into lead gen pipelines, CI/CD, or backend services
• A generous free tier to test before committing
• Sub-500ms responses without headless browser complexity

Best for: indie developers, startups, sales teams, security auditors, and anyone who needs programmatic access without enterprise pricing.

Choose SimilarTech if you need:

• Historical technology adoption data and trend analysis
• Market share reports across industries
• Pre-built lead list exports

Best for: enterprise market research teams and analysts with $299+/month budget who specifically need historical data.

Choose WhatRuns if you need:

• Quick, manual tech checks while browsing
• A free tool with zero setup
• No programmatic integration required

Best for: casual users who check a few sites per week manually and don't need an API.

Quick Start: Try StackPeek Now

curl "https://stackpeek.web.app/api/v1/detect?url=https://stripe.com"

Response:

{
  "url": "https://stripe.com",
  "technologies": [
    { "name": "Next.js", "category": "framework", "confidence": 0.94 },
    { "name": "Cloudflare", "category": "cdn", "confidence": 0.99 },
    { "name": "React", "category": "framework", "confidence": 0.91 },
    { "name": "Stripe", "category": "payments", "confidence": 0.99 }
  ],
  "scanTime": 287
}

No API key required for the free tier. 100 scans per day, zero setup.

The Bottom Line

SimilarTech is a powerful enterprise tool — but at $299/month, it's priced for large teams doing market research. WhatRuns is convenient for manual browsing — but without an API, it can't be integrated into any automated workflow. StackPeek sits in the sweet spot: real-time API detection at a price indie developers and startups can actually afford.

The free tier is live right now. Try StackPeek →