What's the difference between synchronous and asynchronous web scraping?
TL;DR
Synchronous scraping processes one URL at a time, waiting for each to complete before starting the next. Asynchronous scraping handles multiple URLs concurrently, making it significantly faster for scraping many pages. Most modern scraping APIs, including Firecrawl, offer both options.
What’s the difference between synchronous and asynchronous web scraping?
Synchronous scraping processes requests sequentially—scrape URL 1, wait for completion, then scrape URL 2. Asynchronous scraping initiates multiple requests simultaneously and processes results as they complete. For scraping 100 pages, synchronous might take 10 minutes while asynchronous completes in 1-2 minutes.
When to use synchronous scraping
Synchronous scraping is simpler and works well for small jobs. Use it when scraping fewer than 10 pages, when you need immediate results in your code flow, for real-time applications requiring instant data, or when order of results matters.
Firecrawl’s synchronous methods return complete data immediately, making them ideal for quick extractions and prototyping.
When to use asynchronous scraping
Asynchronous scraping excels at scale. Use it when scraping hundreds or thousands of URLs, when speed matters more than immediate results, for scheduled batch jobs, or when monitoring multiple competitors simultaneously.
Firecrawl’s batch scraping and crawl endpoints work asynchronously—submit a job, get a job ID, then check status or receive webhook notifications when complete. This handles large-scale scraping efficiently without blocking your application.
How async scraping improves performance
Instead of waiting for one 5-second request to finish before starting the next, asynchronous scraping initiates 10-20 requests simultaneously. While some complete, others continue processing. This parallelization dramatically reduces total scraping time, especially when network latency dominates.
Key Takeaways
Synchronous scraping processes URLs one at a time, good for small jobs needing immediate results. Asynchronous scraping handles multiple requests concurrently, ideal for large-scale operations. The performance difference is dramatic at scale—async can be 5-10x faster. Most modern APIs like Firecrawl support both approaches, letting you choose based on your use case.
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