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)
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
Prometheus Exporter allows data to export from LiteSpeed Web Servers for use with Prometheus, Grafana, and similar analytics apps
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
Autoindexing
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 Load Balancer
- 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
Programmability
- Lua scripting language
Streaming Media
- VOD: Flash (flv), MP4