Apache Traffic Server vs Squid

Apache Traffic Server is a free, open-source caching proxy server for HTTP/1.1 and HTTP/2. It stores frequently requested pages, images, and web service calls so they can be reused, with the stated aims of improving response time and reducing server load and bandwidth needs. It can also add keep-alive behavior, filter or anonymize requests, and balance traffic through a proxy layer. Deployment patterns include web proxy cache, reverse proxy, and cache hierarchy. As a layer 7 HTTP load balancer, it can choose next-hop servers using request attributes, weighted round robin, or URL consistent hashing. Plug-in APIs let teams add behavior such as changing headers, handling ESI requests, or implementing cache algorithms. Security options include client access controls and authentication, SSL termination, and SSL-based access control. It is self-hosted, with Linux and macOS listed as platforms. The project identifies enterprises, internet service providers, backbone providers, and large intranets as its intended audience. The listed stable release is 10.2.0; 9.2.15 is listed as the long-term support release.

Squid is a self-hosted caching proxy for web traffic. It keeps commonly requested pages and other supported data available for reuse, helping reduce bandwidth and improve response times. Squid handles HTTP, HTTPS, FTP, and gopher data; supported cache engines also include ICP and HTCP. Administrators can apply access controls and use full request logging. Squid can accelerate servers, direct content among web servers, and organize content clusters for load balancing. Multiple caches can be connected as a mesh or hierarchy through parent and sibling links. Proxy authentication options include Basic, NTLM, Digest, and Negotiate, with bundled helpers for LDAP, SQL databases, PAM, RADIUS, and Windows domains. Basic authentication encodes credentials with Base64 rather than encrypting them, so credentials are effectively cleartext between browser and proxy. Squid is free to download, use, and modify, and is distributed under GPL version 2, with some components under compatible open-source licenses. It is available for Linux, macOS, and Windows, with installation through operating-system packages, source releases, and binaries. Documentation, a wiki, bug tracking, and mailing lists are available.