Servlets are supported in nearly
all web servers, from Apache to Zeus. Some web servers support servlets
right out of the box. We call this type of server a Standalone
Servlet Engine. Other web servers require a third-party plug-in
to support servlets. We call the servlet-enabling plug-in an Add-on
Servlet Engine. Finally, if you want to write your own server
with servlet support, you can use what's called an Embeddable
NEW: I've added a section for JavaServer
Pages (JSP) plug-in engines.
This page is a compiled list of the most frequently used servlet
engines. If your favorite engine isn't listed, please write engines-idea at servlets dot com.
Standalone Servlet Engines
A standalone servlet engine is a server that includes built-in
support for servlets. Such an engine has the advantage that everything
works right out of the box. One disadvantage, however, is that you
have to wait for a new release of the web server to get the latest
- The Tomcat Server,
from Project Jakarta (Updated!)
- The open source reference implementation for servlets and JSPs.
Always supports the latest Servlet API revision. It's written
entirely in Java. Source code is available under the excellent
(better than GPL) Apache license as part of Project Jakarta.
It's by far the most
popular servlet engine.
WebSphere Application Server
- A plug-in that's part of an application server. It supports
the full Servlet API on several popular web servers on several
popular operating systems. Includes support for JSP. $795 Standard
Edition, $6,000 Advanced Edition.
BEA Weblogic Application Server
- A high-end server written entirely in Java that supports servlets,
among other things. Formerly
Weblogic's Tengah Application Server. $4,000.
- Caucho's Resin Server
- A servlet engine that prides itself on performance. Works standalone
or coupled with Apache, IIS, or iPlanet/Netscape. It integrates
latest Servlet API and JSP version. It's available under a "Developer
Source" License, where you can see and customize the source but
have to pay for commercial deployment. Prices (as of this writing)
start at $500 per server.
JRun Web Server
- Although it gained prominence as a plug-in (see below), JRun
also includes a full standalone web server and now J2EE application
server. Lets you run a different virtual machine per virtual host
if you need. JRun is free for development, testing, and non-commercial
deployment and contains the full feature set including JSP.
- Orion Application
- A pure-Java web server that supports servlets and JSPs, along
with EJB, JTA, JMS, JNDI, JDBC, RMI/IIOP, XML/XSL, and WAP. Will
be a commercial product but free for non-commercial use.
- Oracle 8i and 9i the Oracle Application Server have built-in
support for servlets. Check out their JDeveloper tool if you plan
to go this route. No pricing information seemed readily available.
Dynamo Application Server
- An application server from ATG (Art Technology Group) written
in Java with support for servlets. Free evaluation. Contact for
- Pramati J2EE Server
- A high-end server and development environment based on J2EE
technologies. They don't say, but it appears to be written in
Java. At least it's available on all the major platforms. Free
30 day evaluation; $1,000 for the Developer Studio; $8,000 per
CPU for deployment; 18% additional per annum for support.
- Borland AppServer
- Borland AppServer 4 includes support for J2EE including servlets
and JSP. Pricing appears to be $895 per developer and $8,500 per
CPU for deployment. Check out
their corp sales web site for more information. An
evaluation download is available.
- Jetty Server
- An open source web server written in 100% Java designed to
stand alone or be embedded (thus shown again below). Supports
Servlet API 2.2 and JSP 1.1 with HTTP/1.1. Also EJBs via a JBoss
integration module. No fee for use as it's distributed under the
Open Source Artistic license.
- The World Wide Web Consortium's
- A full-featured web server written in Java that serves as the
reference HTTP/1.1 implementation. Free.
- Zeus Web Server
- The web server commonly considered the fastest available, now
with servlet support. $1699 per machine.
iPlanet (Netscape) Web Server Enterprise Edition
- The Sun|Netscape Alliance released the iPlanet Web Server Enterprise
Edition (iWS) 4.0. This is the upgrade from Netscape Enterprise
Server 3.x. It supports Servlet API 2.1 that should be really
good. They're so proud of their servlet implementation that in
the FAQ question "Aren't there several freeware contenders?" their
answer is "When measured against freeware competitors like Apache
and bundled products like Microsoft IIS, iPlanet Web Server 4.0
demonstrates an unparalleled Java implementation and considerable
performance advantages". $1495 per CPU. See the Programmer's
Guide to Servlets in Enterprise Server 4.0, especially the
iPlanet (Netscape) Web Server Enterprise Edition for Linux
- The Sun|Netscape Alliance has an alpha of the iPlanet Web Server
Enterprise Edition (iWS) 4.1 for Linux. It supports Servlet API
2.2 (except for WAR files) and JSP 1.1PR1. It's not clear if there
are 4.1 alphas for other platforms.
- Netscape Enterprise
Server 3.5.1 and 3.6
- The most popular web server to provide built-in servlet support.
Unfortunately, NES 3.x supports only the early Servlet API 1.0
and suffers from a number of bugs so significant it's almost unusable.
Users of NES 3.x should upgrade to iPlanet 4.0 (above) or use
an add-on servlet engine. $1295 per CPU.
- The GemStone/J Application Server supports servlets and JSPs.
The base technology is New Atlanta's ServletExec, but GemStone/J
adds multi-process support and automatic HTTP session state distribution
among multiple JVMs running servlets. For pricing, call 800-243-9369
or email email@example.com.
If you are quoted a price, let me know and I'll post it here.
Software's LiteWebServer (Updated!)
- LiteWebServer (LWS) 3.0 is based on Apache Tomcat code, tweaked
and extended for easier installation and management. The additional
code is released under a BSD-style open source license. LWS consists
of a set of modules that can be installed separately, so you only
install and manage exactly the features you need. The Base Module
provides basic web server features (HTTP/1.1 support) and support
for the Servlet API. Add-on modules provide additional features,
such as JSP support. The bundled JustGetIt module manager application
makes it extremely easy to install, upgrade or remove modules.
- A commerical web server written in Java, announced at JavaOne
'99. The company says it "provides linear scalability for Java
servlets". There's a whitepaper on its architecture. Supports
Servlet API 2.0 with 2.1 coming in the last quarter of '99 along
with JSP 1.0. Their slogan is "J-Star, for web sites that must
scale and cannot fail". :-) They say to call for pricing and release
- M5 Web Server
- A commerical web server written in Java. Supports servlets.
Its security model is appealing: SecurityManager sandboxes and
supports throttling by virtual server (limiting denial of service
attacks). I also like its ability to compress output according
to configurable rules! 15 day evaluation. Just $95.
- A small web and application server written in Java. Supports
servlets, JSPs, and HTTP/1.1. Also Server Gateways, SSL, CGI,
SSI, clustering, and Web-based admin. Can use a database for security
controls and server logs. Preview release is free, standard server
is $100, enterprise server (with fail-over, clustering, etc) is
$250. Site-wide licenses of binary and source versions are available.
Domino Go WebServer
- A popular web server with support for servlets. Works with
most platforms. $540.
Paperclips Java Servlet Server 2.0
- A free web server to run servlet. Written in Java; provided
with source. Version 2.1 will be GPL'd.
- jo! Web Server
- Java-based web server that supports Servlet API 2.2, JSP 1.0,
and HTTP 1.1. Requires JDK 1.2. The server is released under what
appears to be an Apache-style license. The JSP executor is GPL.
- KonaSoft Enterprise Server
- A Java application server with support for servlets. $4995
for 100-user version.
- NGASI (Next Generation Application
- Previously called "ELSE", and before that "JAWS". A low priced
servlet engine that supports Servlet API 2.2 and JSP 1.1 and is
optimized to support many virtual hosts and contexts on one or
more CPUs. A license for use without support is just $99 for up
to 1000 contexts, and with support is $499.
- Avenida Web Server
- A small web server built around the servlet architecture.
- A small web server written in Java. HTML administration. Free.
Includes email support.
- A small web server written in Java "based almost entirely upon
servlets". Property file driven. Available under the Gnu Public
WEASEL Application Server
- Contact for information.
Tandem's iTP WebServer
- A web server with servlet support for those with Himalaya systems.
Contact for pricing.
- Novocode's NetForge
- A web server written in Java. Free evaluation, free for non-commercial
- An open source Java application server. Created by Lutris,
now hosted by ObjectWeb..
It supports HTML, XHTML, WML, cHTML, VoiceXML and any other XML
DTD/schema by XMLC, a JDBC O/R mapping tool and IDE plugins with
wizards for Netbeans, Eclipse, Jbuilder and Jdeveloper. It can
also work as add-on for Apache, iPlanet and IIS with connector
modules. The integrated XMLC-based MVC-2 library "Barracuda"
enables model-view-controller based development
of servlet applications. Free under the LGPL. Commercial support
and services can be purchased.
Add-on Servlet Engines
An add-on servlet engine functions as a plug-in to an existing
server--it adds servlet support to a server that was not originally
designed with servlets in mind. Add-on servlet engines have been
written for many servers including Apache, Netscape's FastTrack
Server and Enterprise Server, Microsoft's Internet Information Server
and Personal Web Server, O'Reilly's WebSite, Lotus Domino's Go Webserver,
StarNine's WebSTAR, and Apple's AppleShareIP. This type of engine
acts as a stopgap solution until a future server release incorporates
servlet support. A plug-in also can be used with a server that provides
a poor or outdated servlet implementation.
- The Tomcat Server,
from Project Jakarta
- Tomcat (more information above) also runs as an Apache module,
with work being done to work with Netscape, IIS, and others. Plus,
since the project is open source, if your server isn't listed,
it's only a simple matter of programming...
- Java-Apache Project's
- A servlet engine that adds servlet support to the extremely
popular Apache server. The 1.1 release supports Servlet API 2.0.
This product has been deprecated in favor of Tomcat but it's listed
here for completeness. Free, with source.
- Allaire's JRun Web Server
- A plug-in designed to support the full Servlet API on all the
popular web servers on all the popular operating systems! The
latest version includes a simple web server for development purposes.
JRun is free for development, testing, and non-commercial deployment
and contains the full feature set.
- New Atlanta's ServletExec
- A plug-in designed to support the full Servlet API on all the
popular web servers on all the popular operating systems. Includes
support for JSP. $395.
- An open source Java application server. Sponsored by Lutris
(now out of business). Supports Servlet API 2.2 and JSP 1.1. Has
build-in XMLC and WML support. Works as an add-on for Apache,
iPlanet/Netscape, and IIS. Free. Commercial support can be purchased.
- iServer (more information above) also works as a plug-in for
Apache, Netscape, IIS, and AOL Server.
- Unicom's Servlet CGI
- A framework that supports servlets on top of CGI What it lacks
in efficiency it makes up for in ubiquity, and creativity. Free.
- A plug-in that supports most of the Servlet API on Netscape's
FastTrack Server and Enterprise Server versions 3.x, written in
Java using Nescape's WAI interface. Free. The author Hans Bergsten
reports that the plug-in does not work on iPlanet 4.0 "due to
lack of WAI support in iPlanet 4.0 (it's no longer bundled and
requires you to purchase the Inprise ORB, making a free servlet
container add-on relying on it kind of a moot point)". This proves
why you should be wary of building on vendor-specific technologies.
What was free might start costing money.
Embeddable Servlet Engines
An embeddable engine is generally a lightweight servlet deployment
platform that can be embedded in another application. The application
becomes the true server.
- The Tomcat Server,
from Project Jakarta
- Tomcat (more information above) also works as an embedded engine.
The docs aren't detailed, and there may be some small bugs since
not many people use the server this way, but it's definitely possible.
- iServer (more information above) also works as an embeddable
engine; license starts at $1,500 US to embed the product royalty
free within an application.
- Jef Poskanzer's simple web server that runs servlets "more
of less compatible" with the Servlet API 1.0. Free.
Kristensen's Nexus Web Server
- A servlet runner that implements most of the Servlet API and
can be easily embedded in Java applications. Free, but the server
can be used only for non-commercial use.
Web Core Embeddable Server
- A free but unsupported embeddable web server written in Java.
It incorporates parts of Acme.Serve. Free.
- Jetty Server
- (Please see the earlier listing in the "Standalone" section)
Embeddable JSP Engines
A JSP embeddable engine provides support for JSP in a web server
that already supports servlets.
- This popular open source JSP engine lets you run JSPs on almost
any web server. The project was started by Vincent Partington,
but after he gave up active development many others stepped in
and as of October 1999 have released version 1.0. It supports
JSP 1.0 on top of Servlet API 2.0 or 2.1. (Support on API 2.0
won't be complete as it's not possible.) Free under the GPL.
- Formerly known as Sator, this engine supports JSP 1.1 atop
Servlet API 2.0 or later. You may wonder how that can work since
JSP 1.0 and 1.1 depend on Servlet API 2.1. The answer is that
SJSP on top of Servlet API 2.0 doesn't support JSP forward and
include functionality. They also have a version that supports
JSP 0.92 legacy code. Free for development, contact for commercial
use. Commercial users get source.
- David Creemer's experimental JSP engine. Includes a program
that converts .jsp files to .java servlets directly. David claims
zJSP is intended just for him to play with JSP, but maybe you
want to play too? Free.