How to Build a Fault-Tolerant Rotating Proxy Pool in Python

Web scraping at scale requires more than a single proxy, as IPs can be rate-limited, banned, or timed out by target sites. A robust solution involves building a proxy pool in Python that rotates IPs on every request attempt and retries failed requests using a fresh IP. The approach treats HTTP status codes like 429 and 5xx as retryable errors and applies exponential backoff to avoid overwhelming struggling targets. For multi-step workflows such as logins or cart sessions, sticky sessions allow a fixed IP to persist by pinning a session ID in the proxy credentials. Switching between rotating and sticky modes covers most real-world scraping scenarios without requiring separate infrastructure.