Squid

Squid is a widely used caching proxy server that optimizes web traffic by storing and reusing frequently requested content. It supports multiple protocols and is commonly deployed both as a forward proxy for users and as a reverse proxy (server accelerator) in front of web services.

Key Features

• Caching proxy for web traffic to reduce bandwidth usage and improve response times
• Supports HTTP and HTTPS proxying, plus FTP and additional protocols
• Extensive access controls for controlling and filtering client access
• Can act as a server accelerator (reverse proxy) to reduce origin load
• Flexible request routing to build cache hierarchies and content clusters
• SSL/TLS features for HTTPS handling (including interception modes in supported setups)

Use Cases

• ISP and enterprise forward proxy to optimize outbound web access and control usage
• Reverse proxy cache to accelerate websites and APIs and reduce backend load
• Hierarchical caching deployments to improve throughput across multiple networks

Limitations and Considerations

• HTTPS interception/"bumping" requires careful certificate management and has significant privacy and compliance implications
• Configuration is powerful but can be complex for advanced routing and policy setups

Squid is a mature and performance-focused proxy cache with strong policy controls and deployment flexibility. It is best suited for environments that need bandwidth savings, improved latency, and fine-grained traffic control at the proxy layer.