Popular Soap Engines

Apache Axis, Axis2
Apache Axis is an implementation of the SOAP ("Simple Object Access Protocol") submission to W3C.

Axis (stands for the Apache eXtensible Interaction System) provides transparent access to web services for Java programmers. This allows Java programmers to focus on the business logic of their applications rather than worry low-level network protocols (like SOAP) in order to use a web service.

Apache Axis2 is the core engine for Web services. It is a complete re-design and re-write of the widely used Apache Axis SOAP stack, built on the lessons learnt from Apache Axis.

Apache Axis2 not only supports SOAP 1.1 and SOAP 1.2, but it also has integrated support for the widely popular REST style of Web services . The same business logic implementation can offer both a WS-* style interface as well as a REST/POX style interface simultaneously.

Apache Axis2 is built on Apache AXIOM , a new high performant, pull-based XML object model. Axis2 has support for Spring Framework.

gSoap
gSOAP is a cross-platform development toolkit for C and C++ SOAP XML Web services (SOAP1.1/1.2,WSDL1.1). gSOAP supports XML serialization of native C/C++ data types. Includes SOAP/XML engine, Web server, stub/skeleton compiler, WSDL tools, and much more.

The gSOAP tools provide a SOAP/XML-to-C/C++ language binding to ease the development of SOAP/XML Web services and client application in C and C++. Most toolkits for C++ Web services adopt a SOAP-centric view and offer APIs that require the use of class libraries for SOAP-specific data structures. This often forces a user to adapt the application logic to these libraries. In contrast, gSOAP provides a C/C++ transparent SOAP API through the use of compiler technology that hides irrelevant SOAP-specific details from the user.

The gSOAP stub and skeleton compiler automatically maps native and user-defined C and C++ data types to semantically equivalent XML data types and vice-versa. As a result, full SOAP interoperability is achieved with a simple API relieving the user from the burden of SOAP details, thus enabling him or her to concentrate on the application-essential logic.

Apache Axis2/C
Apache Axis2/C is a Web services engine implemented in the C programming language. It is based on the extensible and flexible Axis2 architecture. Apache Axis2/C can be used to provide and consume WebServices. It has been implemented with portability and ability to embed in mind, hence could be used as a Web services enabler in other software.
Apache Axis2/C supports SOAP 1.1 and SOAP 1.2, as well as REST style of Webservices. A single service could be exposed both as a SOAP style as well as a REST style service simultaneously. It also has built in MTOM support, that can be used to exchange binary data.

Apache Axis C++
Axis C/C++ (Axis CPP) is a non-Java implementation of Axis. At its core Axis CPP has a C++ runtime engine. The provided tooling allows you to create C++ client-side stubs and server-side skeletons. The server skeletons can be deployed to either a full Apache web server using the supplied apache module or a "simple_axis_server" - which is a simple HTTP listener (designed to help you test your services).

There is also limited support for C wrappers around the generated Server and client objects. However, at the current time it is not recommended that these be used in a production environment.

Systinet WASP
Systinet WASP is a platform-independent, standards-compliant set of infrastructure products for building Web services applications in Java and C/C++. WASP also includes the industry's most advanced UDDI registry for companies that need to organize, discover, reuse and manage Web services

SOAPLite:
SOAP::Lite is a collection of Perl modules that provides a simple and lightweight implementation of SOAP, XML-RPC, UDDI and other webservice-related specifications.

PocketSoap
This is an Open Source [MPL] SOAP client COM component for the Windows family, originally targeted at PocketPC (hence the name), there is also a Win32 version that works on Windows 95/98/Me/NT4/2000/XP/2003. The package includes a HTTP 1.1 transport for making HTTP based SOAP requests, however the transport is separate from the main SOAP core, so any other transports can be easily added. James Clark's excellent Expat XML Parser is used for parsing the response SOAP messages.