What's the difference between synchronous and asynchronous web scraping?

Synchronous scraping processes requests sequentially—scrape URL 1, wait for it to finish, then move to URL 2. Asynchronous scraping kicks off multiple requests at the same time and processes results as they come in. For a job covering 100 pages, synchronous scraping might take 10 minutes while asynchronous completes the same work in 1–2 minutes.

When to use synchronous scraping

Synchronous scraping is simpler to implement and works well for small jobs. Choose it when scraping fewer than 10 pages, when you need results returned immediately within your code flow, for real-time applications that require instant data, or when the order of results matters for your processing logic.

Olostep's synchronous methods return complete data immediately, making them ideal for quick extractions and early-stage 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 result delivery, for scheduled batch jobs running in the background, or when monitoring multiple competitors or sources simultaneously.

Olostep's batch scraping and crawl endpoints operate asynchronously—submit a job, receive a job ID, then poll for status or configure webhook notifications for when the job completes. 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 in parallel. This parallelization cuts total scraping time dramatically, especially when network latency is the dominant bottleneck.

Key Takeaways

Synchronous scraping processes URLs one at a time—suitable for small jobs that need immediate results. Asynchronous scraping handles multiple requests concurrently—ideal for large-scale operations where speed matters. The performance difference at scale is significant: async can be 5–10x faster. Modern APIs like Olostep support both approaches, letting you choose based on your specific use case.