How to Detect and Block Web Scrapers
Scrapers steal content, prices and data at scale, usually behind proxies. Learn how to detect scraping by IP and behaviour, and how to block it without harming SEO.
Scraping is industrial-scale copying — of your content, your prices, your catalog — and it's usually automated and disguised. The good news: most scraping rides on detectable infrastructure, so IP intelligence stops a large share of it.
How modern scrapers operate
Serious scraping operations make huge request volumes, so they hide behind proxies to dodge rate limits:
- Datacenter proxies for cheap, fast bulk requests — see what is a datacenter proxy.
- Residential proxies when they need to look like real shoppers — see what is a residential proxy.
- Rotation across thousands of IPs to defeat per-IP limits.
Check whether a scraping IP is a proxy
Detecting scrapers by IP
- Proxy detection — flag datacenter and residential proxies via the proxy detection API.
- Hosting origin — bulk scraping loves cloud servers; datacenter proxy detection catches them by ASN.
- Reputation — repeat offenders carry history.
Add behaviour for the stealthy ones
The hardest scrapers use residential proxies and pace themselves to look human. Layer behavioural signals on top of IP:
- Request velocity and breadth (hitting every product page in order).
- Missing or inconsistent headers and absent JS execution.
- Session shape that no human would produce.
A residential-proxy signal plus machine-like behaviour is a confident scraper verdict.
Block without breaking SEO
The cardinal rule: don't block the crawlers you want.
| Traffic | Handling |
|---|---|
| Verified search-engine crawlers | Allowlist by published/verified ranges |
| Datacenter-proxy requests | Rate-limit hard or block |
| Residential-proxy + bot behaviour | Challenge or block |
| Normal users | Allow |
Implementation
Check the IP server-side on scrape-prone endpoints (search, listings, pricing, APIs), score it, and apply the table. Combine with per-account/per-token limits since IPs rotate.
Bottom line
Scrapers hide behind rotating datacenter and residential proxies, so detect the proxy infrastructure first, then layer behavioural signals for the stealthy residential ones. Allowlist real search crawlers, and rate-limit or block the rest based on a scored verdict.