Squid

Squid acts as a web caching proxy that supports protocols such as HTTP, HTTPS, and FTP. By storing copies of frequently requested pages, it serves subsequent requests from the cache, reducing upstream bandwidth usage and lowering response times for clients. The software includes extensive access‑control features, allowing administrators to define which resources may be cached or served.

It is deployed by many Internet service providers and web sites to accelerate content delivery and to offload traffic from origin servers. Squid can be arranged in hierarchical cache configurations, enabling distributed caching and load‑balancing across multiple servers. This architecture helps to improve network throughput and to handle traffic surges efficiently.

The project is open‑source, released under the GPL‑2.0 license, and runs on a wide range of operating systems, including Windows. It is self‑hostable, free to use without subscription, and considered stable for production environments.