I'm building a tool that extracts structured data from websites, what should I use?

It depends on what kind of websites you’re extracting from and how much structure they already expose. In practice, the best choice is usually a combo of these:

Best options

1. HTML parsing with CSS selectors / XPath

Use this if the site’s pages are mostly static HTML.

• Python: BeautifulSoup, lxml, parsel
• JavaScript/Node: cheerio, jsdom

Pros:

• Fast, reliable, easy to control
• Great for extraction from known page layouts

Cons:

• Breaks when the site redesigns
• Harder on JS-heavy pages

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2. Headless browser automation

Use this if the content is rendered by JavaScript.

• Playwright is usually the best default
• Puppeteer is also solid
• Selenium if you need broader compatibility / legacy setups

Pros:

• Handles dynamic pages, login flows, infinite scroll, client-side rendering
• Can capture rendered DOM after JS runs

Cons:

• Slower and heavier than plain HTTP + parsing

My recommendation: If you're starting fresh, use Playwright.

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3. Structured data extraction from embedded metadata

Many websites expose data directly in:

• JSON-LD
• Microdata
• Open Graph tags
• Meta tags

Look for:

• <script type="application/ld+json">
• itemprop=...
• og:title, og:image, etc.

Pros:

• Often clean and stable
• Less brittle than scraping visible HTML

Cons:

• Not every site has it
• May be incomplete

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4. Website crawling + scraping framework

If you need to scale to many pages/sites:

• Scrapy (Python) is the standard choice

Pros:

• Great for crawling, retries, pipelines, concurrency
• Strong ecosystem

Cons:

• More engineering overhead
• JS rendering needs extra integration

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Best practical stack by use case

If you want the simplest robust setup:

• Playwright + BeautifulSoup/lxml
  • Use Playwright to render pages
  • Extract with CSS selectors or XPath

If the pages are mostly static:

• Requests + lxml/BeautifulSoup
  • Faster and simpler than browser automation

If you need crawling at scale:

• Scrapy
  • Add Playwright only for pages that require JavaScript

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Important things to consider

• robots.txt / terms of service
• Rate limiting and polite crawling
• Retry and backoff logic
• Anti-bot protections
• Normalizing extracted data into a schema
• Logging and test cases for page changes

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Recommendation

If you’re unsure, start with:

Playwright + CSS selectors/XPath + JSON-LD extraction

That gives you the broadest coverage with a good balance of reliability and flexibility.

If you want, I can recommend a stack specifically for:

• Python
• Node.js
• large-scale crawling
• AI-assisted extraction from arbitrary pages