Resolver One

Easy to use, yet powerful

Resolver One is programmable in Python, a programming language designed to be easy to learn and to use, while still being powerful enough for Google and NASA to use in critical operations.

You can use Python both from code, to extend your spreadsheets, and directly from inside formulae. This allows you to combine familiar spreadsheet functions with the expressiveness of Python, giving you the best of both worlds.

Custom functions

Spreadsheet formulae are good for simple things, but when they become complicated they become fragile and difficult to maintain. Resolver One lets you to replace complicated formulae with Python functions, allowing the application of much more interesting calculations.

Custom functions are inherently much more maintainable and auditable, since any change you make in the custom function is applied automatically everywhere it's called. You never have to worry about cells that use an outdated formula, or worry about formulae that have been pasted incorrectly.

See custom functions in action in this short screencast: Custom Functions (1m33s).

Rich interface

Resolver One exposes a programming interface so rich you can build entire applications with it. Change a cell's value, colour, appearance or formatting, create buttons, drop-downs, or new worksheets, cache values between recalculations, and more.


Learning a new programming language and a new program may sound like hard work, but Resolver One's unique architecture makes it easy. In Resolver One, the spreadsheet is the program, so the formulae are turned into Python expressions you can easily copy, paste and modify to your liking.

Modular and reusable

Since Python is a full-featured programming language, you can take advantage of its modularity and extract commonly-used functions, putting them into external modules. That means that you can store them in a central location, keep them under version control and use them from multiple spreadsheets. Also, when a bug is fixed in one module, all the spreadsheets that use that module will pick the change automatically.


Sadly, Resolver One is no longer being actively developed as we focus on our new project, PythonAnywhere.

Last version: 1.9

Resolver One runs on Windows 7, Vista and XP.

We still offer free licenses to selected open-source projects.
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