Resolver One is a Spreadsheet

Spreadsheet

A spreadsheet is a computer application that simulates a paper accounting worksheet. It displays multiple cells usually in a two-dimensional matrix or grid consisting of rows and columns. Each cell contains alphanumeric text, numeric values or formulas...

 program created by Resolver Systems with the IronPython

IronPython

IronPython is an implementation of the Python programming language targeting the .NET Framework and Mono. Jim Hugunin created the project and actively contributed to it up until Version 1.0 which was released on September 5, 2006. Thereafter, it was maintained by a small team at Microsoft until...

 programming language. It is a desktop application, with a web server version, and intended as a platform for the rapid development of business applications. It runs on Microsoft Windows

Microsoft Windows

Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...

, and is free for use in Open Source projects.
.

Resolver One combines the functionality of a spreadsheet and an IDE

Integrated development environment

An integrated development environment is a software application that provides comprehensive facilities to computer programmers for software development...

. Spreadsheets are turned into Python code and executed in real-time. Code can be mixed, using both Python

Python (programming language)

Python is a general-purpose, high-level programming language whose design philosophy emphasizes code readability. Python claims to "[combine] remarkable power with very clear syntax", and its standard library is large and comprehensive...

 and .NET

.NET Framework

The .NET Framework is a software framework that runs primarily on Microsoft Windows. It includes a large library and supports several programming languages which allows language interoperability...

libraries. Spreadsheets can also be exported as stand alone programs.