web server
A web server is computer software and underlying hardware that accepts requests via HTTP (the network protocol created to distribute web content) or its secure variant HTTPS. A user agent, commonly a web browser or web crawler, initia ...
optimized for speed-critical environments while remaining standards-compliant, secure and flexible. It was originally written by Jan Kneschke as a proof-of-concept of the
c10k problem
The C10k problem is the problem of optimizing network sockets to handle a large number of clients at the same time. The name C10k is a numeronym for concurrently handling ten thousand connections. Handling many concurrent connections is a differ ...
– how to handle 10,000 connections in parallel on one server,
but has gained worldwide popularity. Its name is a
portmanteau
A portmanteau word, or portmanteau (, ) is a blend of words ".
Premise
The low memory footprint (compared to other web servers), small central processing unit, CPU load and speed optimizations make lighttpd suitable for servers that are suffering load problems, or for serving static media separately from dynamic content. lighttpd is
free and open-source software
Free and open-source software (FOSS) is a term used to refer to groups of software consisting of both free software and open-source software where anyone is freely licensed to use, copy, study, and change the software in any way, and the source ...
and is distributed under the
BSD license
BSD licenses are a family of permissive free software licenses, imposing minimal restrictions on the use and distribution of covered software. This is in contrast to copyleft licenses, which have share-alike requirements. The original BSD lice ...
. It runs natively on
Unix-like
A Unix-like (sometimes referred to as UN*X or *nix) operating system is one that behaves in a manner similar to a Unix system, although not necessarily conforming to or being certified to any version of the Single UNIX Specification. A Unix-li ...
operating systems, as well as
Microsoft Windows
Windows is a group of several proprietary graphical operating system families developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. For example, Windows NT for consumers, Windows Server for ...
.
Application support
lighttpd supports the
FastCGI
FastCGI is a binary protocol for interfacing interactive programs with a web server. It is a variation on the earlier Common Gateway Interface (CGI). FastCGI's main aim is to reduce the overhead related to interfacing between web server and CGI ...
,
SCGI
The Simple Common Gateway Interface (SCGI) is a protocol for applications to interface with HTTP servers, as an alternative to the CGI protocol. It is similar to FastCGI but is designed to be easier to parse. Unlike CGI, it permits a long-running ...
and CGI interfaces to external programs, allowing web applications written in any programming language to be used with the server. As a particularly popular language, PHP performance has received special attention. Lighttpd's FastCGI can be configured to support PHP with opcode caches (like APC) properly and efficiently. Additionally, it has received attention from its popularity within the Python,
Perl
Perl is a family of two high-level, general-purpose, interpreted, dynamic programming languages. "Perl" refers to Perl 5, but from 2000 to 2019 it also referred to its redesigned "sister language", Perl 6, before the latter's name was offic ...
,
Ruby
A ruby is a pinkish red to blood-red colored gemstone, a variety of the mineral corundum ( aluminium oxide). Ruby is one of the most popular traditional jewelry gems and is very durable. Other varieties of gem-quality corundum are called ...
and Lua communities. Lighttpd also supports WebDNA, the resilient in-memory database system designed to build database-driven websites. It is a popular web server for the
Catalyst
Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...
and
Ruby on Rails
Ruby on Rails (simplified as Rails) is a server-side web application framework written in Ruby under the MIT License. Rails is a model–view–controller (MVC) framework, providing default structures for a database, a web service, and we ...
FastCGI
FastCGI is a binary protocol for interfacing interactive programs with a web server. It is a variation on the earlier Common Gateway Interface (CGI). FastCGI's main aim is to reduce the overhead related to interfacing between web server and CGI ...
,
SCGI
The Simple Common Gateway Interface (SCGI) is a protocol for applications to interface with HTTP servers, as an alternative to the CGI protocol. It is similar to FastCGI but is designed to be easier to parse. Unlike CGI, it permits a long-running ...
chroot
A chroot on Unix and Unix-like operating systems is an operation that changes the apparent root directory for the current running process and its children. A program that is run in such a modified environment cannot name (and therefore normal ...
support
* Web server event mechanism performance – select(), poll(), and epoll()
* Support for more efficient event notification schemes like
kqueue
Kqueue is a scalable event notification interface introduced in FreeBSD 4.1 in July 2000, also supported in NetBSD, OpenBSD, DragonFly BSD, and macOS. Kqueue was originally authored in 2000 by Jonathan Lemon, then involved with the FreeBSD C ...
and
epoll
epoll is a Linux kernel system call for a scalable I/O event notification mechanism, first introduced in version 2.5.44 of the Linux kernel. Its function is to monitor multiple file descriptors to see whether I/O is possible on any of them. It ...
* Conditional
URL rewriting
In web applications, a rewrite engine is a software component that performs rewriting on URLs (Uniform Resource Locators), modifying their appearance. This modification is called URL rewriting. It is a way of implementing URL mapping or routing ...
(mod_rewrite)
*
TLS/SSL
Transport Layer Security (TLS) is a cryptographic protocol designed to provide communications security over a computer network. The protocol is widely used in applications such as email, instant messaging, and voice over IP, but its use in secur ...
with
SNI SNI may refer to:
Science and technology
* Substitution nucleophilic internal, a chemistry reaction mechanism
* Swedish Standard Industrial Classification, a Swedish economic classification system
* Server Name Indication, an extension to the ...
support, via
OpenSSL
OpenSSL is a software library for applications that provide secure communications over computer networks against eavesdropping or need to identify the party at the other end. It is widely used by Internet servers, including the majority of HT ...
RRDtool
RRDtool (''round-robin database tool'') aims to handle time series data such as network bandwidth, temperatures or CPU load. The data is stored in a circular buffer based database, thus the system storage footprint remains constant over time.
...
statistics
* Rule-based downloading with possibility of a script handling only authentication
*
Server Side Includes
Server Side Includes (SSI) is a simple interpreted server-side scripting language used almost exclusively for the World Wide Web. It is most useful for including the contents of one or more files into a web page on a web server (see below), using ...
support (but not server-side CGI from SSI)
* Flexible
virtual hosting
Virtual hosting is a method for hosting multiple domain names (with separate handling of each name) on a single server (or pool of servers). This allows one server to share its resources, such as memory and processor cycles, without requiring al ...
* Modules support
*
Lua programming language
Lua ( ; from meaning '' moon'') is a lightweight, high-level, multi-paradigm programming language designed primarily for embedded use in applications. Lua is cross-platform, since the interpreter of compiled bytecode is written in ANSI C, ...
scripts via mod_magnet
*
WebDAV
WebDAV (Web Distributed Authoring and Versioning) is a set of extensions to the Hypertext Transfer Protocol (HTTP), which allows user agents to collaboratively author contents ''directly'' in an HTTP web server by providing facilities for con ...
support
*
HTTP compression
HTTP compression is a capability that can be built into web servers and web clients to improve transfer speed and bandwidth utilization.
HTTP data is compressed before it is sent from the server: compliant browsers will announce what methods ar ...
using mod_deflate (zlib, brotli, zstd)
* Light-weight (less than 1 MB)
* Single-process design with only several threads. No processes or threads started per connection.
* HTTP/2 support since lighttpd 1.4.56
* HTTP/2WebSocket support since lighttpd 1.4.65
Limitations
* Versions below 1.4.40 do not officially support sending large files from CGI, FastCGI, or proxies unless X-Sendfile is used. This limitation has been removed in lighttpd 1.4.40.
* No
HTTP/3
HTTP/3 is the third major version of the Hypertext Transfer Protocol used to exchange information on the World Wide Web, complementing the widely-deployed HTTP/1.1 and HTTP/2. Unlike previous versions which relied on the well-established TCP ...
support
Usage
Lighttpd was used in the past by several high-traffic websites, including
Bloglines
Bloglines was a web-based news aggregator for reading syndicated feeds using the RSS and Atom formats. Users could subscribe to the syndicated feeds for free using a web browser. Bloglines offered an application programming interface that maint ...
Meebo
Meebo (often stylized as meebo) was an instant messaging and social networking service provider. It was founded in September 2005 by Sandy Jen, Seth Sternberg, and Elaine Wherry, and was based in Mountain View, California. Initially the company ...
, and
YouTube
YouTube is a global online video sharing and social media platform headquartered in San Bruno, California. It was launched on February 14, 2005, by Steve Chen, Chad Hurley, and Jawed Karim. It is owned by Google, and is the second mo ...
. The
Wikimedia Foundation
The Wikimedia Foundation, Inc., or Wikimedia for short and abbreviated as WMF, is an American 501(c)(3) nonprofit organization headquartered in San Francisco, California and registered as a charitable foundation under local laws. Best know ...
Proxy server
In computer networking, a proxy server is a server application that acts as an intermediary between a client requesting a resource and the server providing that resource.
Instead of connecting directly to a server that can fulfill a reques ...
which discusses client-side proxies
* Reverse proxy which discusses origin-side proxies
*
Traffic Server
The Apache Traffic Server (ATS) is a modular, high-performance reverse proxy and forward proxy server, generally comparable to Nginx and Squid. It was created by Inktomi, and distributed as a commercial product called the Inktomi Traffic S ...
*
Web accelerator
A web accelerator is a proxy server that reduces website access time. They can be a self-contained hardware appliance or installable software.
Web accelerators may be installed on the client computer or mobile device, on ISP servers, on the serve ...