This section of the documentation provides information about Saxon licensing, including required notices for open-source components that have been incorporated into Saxon, and acknowledgments of contributors.

This documentation relates both to the open source Saxon-HE product and to the commercial products Saxon-PE and Saxon-EE. The conditions of use are of course different in the two cases; there are also differences in the third-party components that are included.

The information in this section applies to both the Java and .NET versions of Saxon, unless otherwise specified.


The open-source Saxon-HE product is made available under the Mozilla Public License (the "License"). Prior to Saxon 9.5 MPL Version 1.0 was used; from 9.5 onwards, MPL Version 2.0 is used. You may not use the software except as permitted by the License. You may obtain a copy of the License at

MPL version 2.0 allows software to be declared as "compatible with secondary licenses". Saxon code, in general, is NOT compatible with secondary licenses. This means it is not possible to redistribute the source code under a different license. The reason for this is the difficulty of obtaining the consent of all past contributors to the code.

The source code of Saxon can be considered for licensing purpose as having three parts:

Saxon-HE includes a separate JAR file, saxon9-xqj.jar, which contains Saxon's support for the XQJ interface, a standard API for access to XQuery engines from Java. In previous Saxon releases this was made available as part of the main JAR file. It has been decoupled because it has been pointed out that the license under which Oracle distribute XQJ is not a pure open source license under the definition used by the Open Source Initiative: specifically, it does not allow modifications, and it does not allow redistribution except as part of a product that satisfies all the compatibility tests. Saxon satisfies these conditions, but some users are only prepared to use code that conforms to OSI-approved licenses. If you fall into this category, please delete the saxon9-xqj.jar file. (In Saxon-PE and Saxon-EE, the XQJ components are delivered as part of the main Saxon JAR file.)

Also distributed with Saxon-HE is a JAR file, saxon9-unpack.jar, which contains proprietary Saxonica code (non-open-source) for executing a "packaged" stylesheet that has been prepared under Saxon-PE or Saxon-EE. For details of this feature see Packaged Stylesheets (Note, this feature is retained from earlier Saxon releases and is unrelated to the concept of a package as defined in XSLT 3.0). This JAR file can be freely redistributed, but in all other respects, the terms and conditions published at apply. If you do not want to accept these conditions, please delete this JAR file.

Saxon-EE and Saxon-PE

The Enterprise and Professional editions of Saxon are commercial products released under the terms and conditions published at

These products include some open source components. Although your contract with Saxonica is entirely defined by the commercial license, the existence of an open source license for these components gives you additional rights, which are described in this section. The source code for Saxon-PE and Saxon-EE can be considered to be in three parts:

  1. Source code for which Saxonica Limited owns the copyright, which Saxonica has chosen to make available to the public under the Mozilla Public License version 2.0 (around 250K lines of code)

  2. Source code for which Saxonica Limited owns the copyright, which Saxonica has chosen to retain as proprietary (around 90K lines of code)

  3. Open source code developed and licensed by third parties and used by Saxonica under the terms of those licenses (around 20K lines of code)

The code in the third category is in most cases also used in Saxon-HE (the only open source code in Saxon-PE or Saxon-EE that is not also used in Saxon-HE is the ASM bytecode generation library and the ICU localization library). In all cases the license under which the code was used permits the creation of commercial products derived from this code, and does not "infect" such products with open source obligations. In many cases the relevant license requires a notice to be published; this is satisfied by inclusion of the relevant notices in this docoumentation and also in the notices directory of the issued product. In many cases the relevant license also requires any modifications to source code to be published; Saxonica satisfies the requirement by issuing the source code of Saxon-HE, which includes all such modifications.

From Saxon 9.5, the different editions of the product (other than Saxon-CE) are built from a common source code base, and the first stage of building the product involves a preprocessor step, which in some cases removes selected code. The common source code for a Saxon-HE module, for example, might include a call to a function that is only present in Saxon-EE, and the preprocessor step removes this call. Saxonica therefore makes "source code" available in two forms:

The Saxon SQL extension

The Saxon SQL extension is available as an open-source plug-in to Saxon-PE or Saxon-EE. It will not run with Saxon-HE because it relies on XSLT element extensibility, a feature not available in Saxon-HE. However, the code of the SQL extension itself is open-source and is issued under the Mozilla Public License, meaning that you are free to extend it and customize it to your needs, even though it requires Saxon-PE or Saxon-EE to run.

EXSLT extensions

A substantial number of extension functions defined in EXSLT are available as an open-source plug-in to Saxon-PE or Saxon-EE. Many of these are implemented as reflexive extension functions, and therefore rely on a mechanism not available in Saxon-HE. However, the code of the these extension functions itself is open-source and is issued under the Mozilla Public License 2.0, meaning that you are free to extend it and customize it to your needs, even though it requires Saxon-PE or Saxon-EE to run.

Note: this does not apply to implementations of the EXPath extension functions, which in Saxon 9.6 are implemented in code that is Saxonica-proprietary.


Redistribution of Saxon-HE is freely permitted under the terms of the Mozilla Public License 2.0. Note that this requires inclusion of all the necessary notices. If any source code changes are made, the license requires that they be published (or at any rate, made available to your users); but you are not required to publish the source of your own application code if it is in separate modules.

If you produce a product that includes or requires Saxon-HE, please refer to it prominently as "The Saxon XSLT and XQuery Processor from Saxonica Limited", and include the URL of the home page, which is at As a courtesy, please take reasonable steps to ensure that your users know that they are running Saxon.

Redistribution of Saxon-PE or Saxon-EE as a component of a commercial application is possible under commercial terms; prices are published in the Saxonica online store, and a specimen contract will be supplied on request.

Technical Support (Saxon-HE)

Software distributed under the License is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License for the specific language governing rights and limitations under the License.

There is no guarantee of technical support, though we are usually able to answer enquiries within a few days. Please use the bug trackers and support forums provided on the community site at There is also a mailing list available at Please check the bug tracker at for details of known errors; all bugs are listed there, whether they apply to the open-source or commercial versions of Saxon.