I’m building a web scraping application that needs to run multiple browser instances simultaneously across different threads. I’ve tested several headless browsers but keep running into limitations.
Current findings:
- HtmlUnit lacks reliable JavaScript execution
- QtWebKit’s QWebPage has thread safety issues
- PhantomJS requires separate processes which isn’t ideal for my use case
- Awesomium doesn’t support multi-threading properly
I need recommendations for headless browsers that can:
- Execute JavaScript reliably
- Create new instances from different threads safely
- Handle concurrent operations without conflicts
The programming language doesn’t matter to me. Has anyone found a good solution for thread-safe headless browsing with proper JS support?
Chrome headless with Selenium works great for multi-threaded scraping. Each thread gets its own Chrome instance, no interference, and JS execution is rock solid since you’re using the real Chrome engine. I’ve run dozens of concurrent instances without problems. Just make sure each thread has its own WebDriver object and manage your driver instances properly. Yeah, memory usage gets heavy with lots of instances, but the reliability’s worth it. Also check out Playwright - way better resource management and handles concurrent stuff really well.
Firefox headless is perfect for this. Geckodriver handles threading way better than most people think - I’ve got production scrapers running 15-20 Firefox instances at once with zero stability problems. Just make sure you’re using separate profile directories for each thread and isolate your driver initialization properly. Firefox’s JS engine crushes complex sites that break other headless browsers. Memory usage beats Chrome, and it recovers from crashes really well. Want something lighter? Try Playwright with Firefox backend - you get the same threading benefits but with better resource management than straight Selenium.
hey, yeah, puppeteer is pretty great for what ur needing! it allows multiple instances and does js really well. i had good experience with it for scraping too. might be worth a shot!