IP whitelisting (or allowlisting) is a security control that grants access only to requests from pre-approved IP addresses. Proxy providers offer static IPs or username-based authentication so customers can add proxy IPs to their target's allowlist without exposing credentials in every request header.
For web scrapers accessing APIs legitimately, whitelisting your proxy provider's egress IPs eliminates per-request auth overhead and reduces latency. Some enterprise SaaS products require IP whitelisting as part of security compliance — meaning automated workflows using them need stable, predictable IP ranges rather than rotating pools.