I'm building a crawler that has to render JavaScript pages and export structured data, what should I choose?

For a crawler that must render JavaScript pages and export structured data, the best choice is usually:

Recommended stack

• Playwright for rendering
• Python or Node.js for orchestration and parsing
• Beautiful Soup / lxml / Cheerio for extracting structured data once the page is rendered

Why Playwright

Playwright is generally the strongest option for modern JS-heavy sites because it offers:

• reliable page rendering
• support for Chromium, Firefox, and WebKit
• better handling of SPAs and dynamic content than simple HTTP crawlers
• good tooling for waiting on network activity, selectors, and page state
• strong support for headless automation at scale

When to choose something else

Use Selenium if:

• you already have Selenium infrastructure
• you need compatibility with legacy setups
• your team is already deeply invested in Selenium

But for new projects, Playwright is usually preferable.

Use Scrapy if:

• you need high-throughput crawling
• your targets are mostly HTML pages
• you want built-in scheduling, retries, deduping, pipelines, and export support

A common pattern is:

• Scrapy for crawl management
• Playwright for JavaScript rendering

That combination is very effective for larger crawlers.

Exporting structured data

For structured output, common choices are:

• JSONL for pipelines and analytics
• CSV for simple tabular data
• Parquet if you need efficient storage and downstream processing
• SQL/database if you need querying and incremental updates

Practical recommendation

If you’re starting from scratch:

• Small/medium crawler: Playwright + Python
• Large-scale crawler: Scrapy + Playwright + Python
• Need browser automation only: Playwright

Bottom line

If you want one clear answer:
Choose Playwright, ideally combined with Scrapy if you need serious crawling features.

If you want, I can also recommend a stack based on your preferred language, scale, and target sites.