How I Built an Async FastAPI Microservice to Extract Tech Stacks, SEO & B2B Contacts in <1s

Burhan Şahin — Wed, 02 Sep 2026 21:26:55 +0000

Hey fellow developers! 👋

When auditing client websites or building lead-generation pipelines, the typical solution is to fire up heavy headless browsers (Playwright/Puppeteer) or subscribe to expensive enterprise APIs that charge thousands of dollars a year.

I wanted a lightning-fast, lightweight alternative that could run asynchronously and return structured intelligence in under 1 second.

So I engineered a dedicated FastAPI microservice: B2B Web Intelligence & SEO Lead Engine.

🛠️ Architecture & Under the Hood

The service is built on:

FastAPI (Python 3.12): Utilizing fully asynchronous request lifecycles.
HTTPX: High-performance async HTTP client for concurrent domain inspection.
BeautifulSoup4 & Regex Fingerprinting: Fast HTML parsing without browser engine overhead.

⚡ What It Extracts in 1 Single Request:

Tech Stack Fingerprinting: Accurately detects CMS platforms (WordPress, Shopify, Webflow, Wix), frontend frameworks (React, Vue, Next.js), and analytics trackers (Google Analytics, Segment).
SEO & Social Metadata: Meta title, meta description, canonical URL, OpenGraph cards, Twitter cards, and H1-H6 heading structure.
B2B Contact Extraction: Scrapes public corporate emails, phone numbers, and direct social profile links (LinkedIn, Twitter/X, GitHub, Instagram).
Security & Performance: SSL certificate validity check, HTTP security headers, and precise response latency in milliseconds.

🚀 Try It Live (Interactive Swagger / Docs)

The service is deployed live. You can test endpoints directly in your browser:
👉 Live OpenAPI Docs: https://b2b-web-intelligence-api.onrender.com/docs

It is also published on RapidAPI with a free tier (50 requests/mo for developers to test):
👉 RapidAPI Marketplace: https://rapidapi.com/SwampieB/api/b2b-web-intelligence-and-seo-lead

💬 Feedback Welcome!

I'm actively refining the tech-detection signatures. If you test your company domain or portfolio site:

Did it accurately detect your framework/CMS?
What other data points would be valuable for your workflow (e.g. DNS records, sitemap parsing)?

Drop your thoughts in the comments below!

DEV Community: Burhan Şahin

How I Built an Async FastAPI Microservice to Extract Tech Stacks, SEO & B2B Contacts in <1s

🛠️ Architecture & Under the Hood

⚡ What It Extracts in 1 Single Request:

🚀 Try It Live (Interactive Swagger / Docs)

💬 Feedback Welcome!