How do I scrape websites without getting blocked?
Work with the site rather than trying to overpower it. Check the terms and robots.txt, know what is lawful before you pull anything, slow your requests, keep concurrency modest, cache what you already have, and stop re downloading pages that have not changed.
A proxy helps with geographic testing and with spreading legitimate traffic across more addresses. It does not fix careless request behaviour, and no pool is large enough to outrun a pattern that looks automated.
Four habits make more difference than most people expect.
- Keep sessions stable for anything multi step, rather than changing identity partway through a flow.
- Back off on failure in measured steps instead of retrying harder, which is how a slow down becomes a block.
- Watch your response codes rather than only your throughput. A page quietly returning cached or default content is more dangerous than one returning an error, because it poisons your data without alerting you.
- Collect only what you need, and respect the rules covering personal data.
Worth knowing
If the site publishes an official API or a data export, use it. It is faster, more reliable, and it does not depend on the site never changing its markup.
Other questions
These answers describe how the NullVault proxy network works in practice, across residential, ISP, mobile, datacenter and IPv6 pools.