Creating XML and JSON comparison toolkits since 2001

We are completely focused on managing change to structured information. Our comparison and merge software tools transform the way our customers handle change in their XML documents, XML data and JSON files.

Where change matters

We have been working on XML comparison for almost as long as XML has existed and our first product was formally launched in 2001. Since then, tens of thousands of people in hundreds of companies have benefited from using our products. Although XML is in our name and was our initial focus, JSON is a natural step for us as a popular format for structured data.

The Management Team

Meet the people behind DeltaXML

Robin La Fontaine

Founder and CEO

Robin is the founder of DeltaXML. With a background in Engineering Science (Oxford) and a masters in Computer Science, his software career includes computer aided design and much of the DeltaXML technology originates from this area – the management of change in electronic circuits is a complex problem where accuracy is critical. He has grown DeltaXML from very small beginnings to a leading position with major corporate and public sector customers. Keeping information up to date is a constant challenge, and those that manage change well gain a significant competitive advantage.

Mark Thomas

Chief Operating Officer

Mark is COO of DeltaXML working across the business and brings with him experience as a successful entrepreneur and developer working in all areas of the digital space for over 30 years. A board member for over 20 years with several organisations, he was a runner-up Welsh Young Businessperson of the Year in 2001, and a Business Insider Rising Star. Mark founded, owned and ran VSI-thinking, which developed web software and applications, for 17 years before being acquired in 2015 with support from Development Bank of Wales.

Tristan Mitchell

Product Director

One could argue that playing ‘Arcadians’ on the Acorn Electron back in the 1980s was the real beginning of Tristan’s computing career. Tristan’s official education and passion for computing came in the computer science classes he took at high school, leading him to the University of Wales, Aberystwyth to complete an MEng in Software Engineering. Tristan has been working with DeltaXML for over ten years, and in that time has contributed much, driving DeltaXML to its place as a market leader in the XML document and data comparison industry.

Bridget Mason

Director of Marketing

A highly efficient, innovative and proactive marketer Bridget is a Fellow of the Chartered Institute of Marketing and has over 25 years’ experience developing B2B marketing and communication activities to help organisations achieve their goals.

Bridget initially worked with DeltaXML as a coach and mentor to the marketing team before joining part-time as Marketing Director to help grow the business and create a strategy to make this happen. Known for being extremely organised and highly motivated she is passionate about what she does, whether it is aligning business goals with marketing strategies, measuring current plans and campaigns to see what results are being achieved, or being creative in coming up with new ideas to drive lead generation, brand recognition or loyalty.

We’ll be happy to have you.

So serious we got certified

We understand that people rely on our software and that it performs a critical role in many organisations, from government and finance to aerospace and research. We believe we have a serious responsibility to live up to their expectations, delivering ever better and always high quality software and support.

We have been accredited with ISO 9001 and ISO 27001.

ISO 9001 is the world’s most recognised management standard. It is based on a number of quality management principles including a strong customer focus, the motivation and implication of top management, the process approach and continual improvement.

ISO 27001 was awarded to us due to the proof that DeltaXML prioritises data security. Customer data is rigorously protected and we strive everyday to assess, minimise and eliminate any and all risks and vulnerabilities.

We’ll bring the tea

Headquartered in Worcestershire, UK our offices are surrounded by the luscious hills of Malvern. Don’t allow the humble surroundings to deceive you, however, we’re trusted around the world by SMEs to global enterprises.

Read Customer Stories →


  • 2021

    Improved functionality for XML Compare

    Version 11 of XML Compare released, including significant improvements in performance of the core comparison engine and more flexible licensing mechanisms for cloud deployment.

  • 2020

    DeltaJSON arrives

    Our first non-XML product, DeltaJSON, launched. This is an online REST service for comparing and merging JSON files with advanced handling for large JSON arrays.


  • 2019

    Adding REST API and handling XML data

    Version 10 of XML Compare saw a REST interface and we introduced our new product XML Data Compare which launched with new algorithms to handle large and complex XML data files, with advanced alignment of data that can appear in any order.

  • 2018

    More office space

    We extended our office at Malvern Hills Science Park to double the office size.


  • 2017

    XML Core becomes XML Compare

    Version 9 of XML Core came with a re-branding to XML Compare and the ability to generate Adobe Framemaker tracked changes.

  • 2016

    Improving licensing

    Version 8 of XML Core introduced a new licensing mechanism to meet the needs of both customers and OEM distributors.


  • 2015

    Our first XML merging software launched

    Our XML Merge product launched to merge 3 or more files and we did this while expanding our office space in the Malvern Hills Science Park.

  • 2014

    Handling change in tables

    Version 7 of XML Core came with significant new capability for XML documents including handling of tabular data in CALS and HTML and generating tracked changes for oXygen, Arbortext and other XML editors.


  • 2013

    Staying friendly with a new office

    We moved to new office at the Malvern Hills Science Park and installed environmentally friendly heat pumps for office heating and cooling.

  • 2013

    Applied for third patent

    This patent covered changes to the structure as well as the content of three or more markup language files.


  • 2010

  • 2008 - 2010

    2 more releases of XML Core

    The version 5 release of XML Core used the newly patented representation of multiple files, while version 6 released with more flexible architecture for handling different types of document.

    2008 - 2010

  • 2007

    Applied for Second Patent

    This patent covered changes to three or more markup language files.

  • 2002 - 2006

    XML Core released with more features

    3 different versions of XML Core were released during this time, version 4 of XML Core launched with new deep matching algorithm for better alignment of document sections and paragraphs and capability for word-by-word changes.

    2002 - 2006

  • 2001

    DeltaXML Core Application Launched

    XML Core was released and we won our first customer who remained with us for 10 years. Our second customer has been with us for 20 years as an OEM customer although the original company has been taken over by IBM.

  • 2000

    Applied for First Patent

    To cover representation of change in markup language files, which was awarded several years later in Europe and USA.


  • 1998

    XML Standard Launched

    We identified this as a significant opportunity as a standard format for data. Therefore we wanted to migrate previous work on the management of change to apply this to XML, and we started to develop software to implement this.

  • June 1991

    Monsell EDM Ltd formed as a consultancy company

    Just founder Robin La Fontaine with contractors. We worked for a US standards organisation, the EIA, to develop an interchange standard for electronic designs, schematic and printed circuit boards, known as EDIF (Electronic Design Interchange Format, or the colloquial alternative Every Day Is Friday!).

    June 1991

DeltaXML Products

Browse our sophisticated toolkits for comparing and merging XML and JSON files. Flexible APIs and highly configurable outputs are ideal for integration into your enterprise systems or embedding into your own products.

XML Compare
XML Data Compare
DITA Compare
DocBook Compare
XML Merge
DITA Merge

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