This open source community project supports Varian collaborators and customers in their work with Varian Medical Systems public APIs. Replacement for CodePlex.


This is the home for the Varian API book, legacy code examples, Velocity Engine and PyESAPI. There is some addional content in the Wiki.

Varian Developer Support

Current offical developer discussions are hosted in the community section of

Varian API Book


Varian Code Samples

Explore code samples from past webinars and workshops here:

Velocity Engine

Python and C# Velocity Scripting API clients:


Python interface to Eclipse Scripting API:

MyVarian Webinars

What’s New

2019+ Updates see

02/21/2019 Community driven forum to ask ESAPI developer questions, promote open source code, and engage in discussion involving clinical scripting posted to in the ESAPI SubReddit

08/02/2018 Wiki Restored from CodePlex:

04/04/2018 We’ve moved from CodePlex to GitHub, stay tuned! (CodePlex Archive)

06/29/2017 Quick Start with ESAPIX posted on Youtube.

04/24/2017 Async and await in ESAPI posted on Youtube.

04/24/2017 Unit testing in ESAPI posted on Youtube.

09/08/2016 Updated Export3D. Now it includes separate Bolus export with vertex normals, for 3D printing. Thank you Nathan Smela!

07/21/2016 See Advanced ESAPI #2 on Youtube

03/17/2016 Save the date for Varian Developer Workshop 2016! July 29th & 30th, Washington, D.C.

10/20/2015 See EvilDICOM in ESAPI on Youtube for DICOM file exporting.

10/07/2015 See Advanced ESAPI #1 on Youtube and source code on

06/10/2015 Eclipse Scripting REPL (UAB VMS Console) Video and Source Code Posted

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