freenginx vs Redbird

freenginx is an effort to preserve free and open development of server software used for HTTP, mail, and TCP/UDP proxying. Its HTTP server can serve static files, reverse proxy with caching, balance load, and provide fault tolerance. It supports SSL/TLS SNI, HTTP/2, and HTTP/3, along with access controls based on client IP address, HTTP Basic authentication, or a subrequest result. Cached and accelerated connections are available for FastCGI, uwsgi, SCGI, and memcached servers. The mail proxy supports IMAP, POP3, and SMTP authentication methods with SSL and STARTTLS/STLS. TCP and UDP proxying includes load balancing, fault tolerance, and client-address access control. The process design uses one master and several workers running under an unprivileged user. Configuration can be reloaded and the executable upgraded without interrupting client service. Source and documentation are distributed under a 2-clause BSD-like license. The software is self-hosted and uses file-based configuration; downloads include source, Windows builds, and mainline and stable versions.

Redbird has no write-up on Specifiction yet; its figures are above.