Main Features

Event-driven architecture with extremely low resource (CPU and RAM) overhead
Handles hundreds of thousands of concurrent connections without load spikes
High-performance coding using kqueue (FreeBSD and OS X), epoll (Linux), /dev/poll (Solaris), and poll
Worker processes for scalability. Ability to bind certain processes to particular workers
WebAdmin GUI with build-in real-time statistics graphical dashboard
Rewrite engine uses Apache mod_rewrite syntax
Support of third-party modules through API (LSIAPI)
High-performance page caching

Performance Features

Reduce Bandwidth Usage
  • Sendfile() support
  • Gzip compression
  • Brotli compression for static files
Even Faster Technologies
  • HTTP/3 and QUIC
  • All version of SPDY/2, 3, 3.1 and HTTP/2 support
  • Pipelined requests
  • TCP_FASTOPEN support
  • HTTP/2 Server Push

External Applications Support

Supports PHP, Ruby, Python, Perl, and Java external applications
LSAPI, a LiteSpeed-native SAPI, greatly improves PHP, Ruby, and Python speeds
Delegates external applications to separate processes, increasing efficiency
Buffers requests and responses to external applications to more efficiently serve multiple connections
Efficient CGI daemon
Compatibility with third party PHP accelerators
More efficient communications, controlled number of processes, and less web server resource usage increases scalability of web applications

Security Features

SSL Support
  • Apache-compatible SSI support
  • SSL support and hardware acceleration
  • TLS 1.0, 1.1, 1.2, 1.3
  • Anti SSL BEAST and renegotiation attack capabilities
  • libressl support
Security Controls
  • Bandwidth and connection throttling
  • IP-based access control
  • Strict HTTP request validation
  • Referer limiting
  • Response rate limiting
Server Alert
  • Buffer overrun guards

Stability Features

Graceful restart feature allows application of configuration changes and upgrades without server downtime
Fault tolerance and instant restarting
Runs completely in user space. OS reliability is not affected

Basic HTTP Server Features

Unlimited concurrent connections
Accept-filters and TCP_DEFER_ACCEPT support
Chunked transfer encoding
Keep-alive connections
IPv4 and IPv6
Entity tags
Multi-range requests
Exact/prefix/regex-based matching
Unlimited name-based and IP-based virtual hosting
Custom error pages
Set Cache‑Control headers

Advanced Features

Easy virtual host configuration via templates
Easily run multiple versions of PHP on one server
Build-in tool for compile PHP module
Can send logging to logging server
XML or flat file configuration
Smart server push
OCSP stapling
Advanced Modules
  • PageSpeed Module support
  • GeoIP modules to locate users by IP address (requires MaxMind GeoIP database)
As LoadBalancer
  • Support HTTP/HTTPS
  • Build-in Round Robin Policy
As Proxy
  • WebSocket proxy support
As Reverse
  • Accelerate static content delivery, compress throughput
  • Proxying With Context / Rewrite Rules / Script Handlers
  • Lua scripting language
Streaming media
  • VOD: Flash (flv), MP4