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 SaxonJ-HE product and to the commercial products (SaxonJ-PE, SaxonJ-EE, SaxonCS). 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 SaxonJ and SaxonCS, unless otherwise specified.

The source code of Saxon can be considered for licensing purposes as having four parts:


The open-source SaxonJ-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.

SaxonJ-HE is built from code in categories A, B, and C above. This code is published and is available for use under the terms of the license. Most users will never need access to source code, but for those who do, it is published in two forms:

  • Saxonica's open-source Git repository at contains the source code in the form required by the MPL license, that is, "the form of the work preferred for making modifications". This form of the code includes preprocessor directives used to identify variations between the code for different Saxon editions, and it therefore cannot be compiled until the preprocessor has been run. The repository includes gradle build files that invoke this preprocessing. The build files are complex and have many dependencies. Many users will therefore find it easier to build from the preprocessed source published on GitHub.

  • For every release, a ZIP file containing Saxon-HE source is published in the Saxonica Saxon-HE GitHub repository. A typical file name is This is the source code after preprocessing to extract the code needed for building SaxonJ-HE, and it is possible to compile it simply by dropping it into the source directory structure for an IDE such as Eclipse or IntelliJ, provided all the required third-party libraries are present on the classpath.

Saxonica does not actively solicit contributions to the code from external developers. We will accept contributions only if the requirements and design have been agreed in advance, if comprehensive test material is supplied in a suitable form, and if a contribution agreement is signed.

SaxonJ-HE includes a separate JAR file, saxon-xqj-12.x.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 distributes 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 saxon-xqj-12.x.jar file. (In SaxonJ-PE and SaxonJ-EE, the XQJ components are delivered as part of the main Saxon JAR file.)

SaxonJ-EE and SaxonJ-PE

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

From Saxon 11, licenses are issued as term licenses rather than perpetual licenses: that is, they have an expiry date. Please take care to order a replacement license so that it can be installed before the old one expires. Replacement licenses will always run until the anniversary of the original expiry date, so there is no penalty for reordering early. If you do allow a license to expire before a replacement is installed, then to minimize inconvenience, the software will degrade gracefully: every time an application starts up, there will be a delay which increases progressively each day.

Existing perpetual licenses will continue to work with Saxon 11 until their upgrade entitlement period ends. The upgrade entitlement period is normally one year from the date of purchase, unless you chose to pay for a longer term.

These products include some open source components. In particular, they include the open-source components used to build Saxon-HE (categories A, B, and C above) in their entirety; they also include some open-source components (notably the ICU library) which are not used in Saxon-HE. 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 above.


SaxonCS is a commercial Saxonica product built from the following components:

  1. The Java source code of SaxonJ-EE (see above), converted to C# using a Saxonica-produced transpiler. The transpiler is written largely in XSLT 3.0, but also makes use of the open-source javaparser library.

  2. Additional Saxonica-owned code written in C#, to provide a C# API and to integrate with .NET components such as the System.Xml.XmlReader parser.

  3. Third party libraries referenced by means of nuget dependencies. These libraries are downloaded automatically as part of the installation process; in addition, they are bundled into the platform-specific executables issued with the product. The relevant libraries are:

    • AngleSharp
    • ICU4N
    • ICU4N.Collation
    • ICU4N.CurrencyData
    • ICU4N.LanguageData
    • ICU4N.RegionData
    • ICU4N.Transliterator
    • Microsoft.AspNetCore.StaticFiles
    • Org.XmlResolver
    • Org.XmlResolverData
    • Singulink.Numerics.BigDecimal
    • Singulink.Numerics.BigIntegerExtensions
    • System.Collections.Immutable

    For the specific licensing conditions attached to each of these libraries, please see the relevant data in nuget.

The Saxon SQL extension

The Saxon SQL extension is available as an open-source plug-in to SaxonJ-PE or SaxonJ-EE (on the Java platform only, not available on the .NET platform). It will not run with SaxonJ-HE because it relies on XSLT element extensibility, a feature not available in SaxonJ-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 SaxonJ-PE or SaxonJ-EE to run.

EXSLT extensions

A substantial number of extension functions defined in EXSLT are available as an open-source plug-in to SaxonJ-PE or SaxonJ-EE. Although not shipped with Saxon-HE, 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 SaxonJ-PE or SaxonJ-EE to run. (See EXSLT extensions for more information on the functions available.)

In SaxonCS, just two EXSLT extension functions are available, both in namespace specifically the node-set() and object-type() extensions. Although these serve no useful purpose with XSLT 2.0 and later versions, they have been implemented because they are widely used in XSLT 1.0 stylesheets. The implementation is under the same license conditions as the rest of SaxonCS.

Note: this does not apply to implementations of the EXPath extension functions, which since Saxon 9.6 are implemented in code that is Saxonica-proprietary. (See EXPath extensions for more information on the functions available.)


Redistribution of SaxonJ-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 SaxonJ-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 commercial Saxonica products (SaxonJ-PE, SaxonJ-EE, SaxonCS) 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.