relax is an open source and freely distributed software project that has been designed for studying molecular dynamics by analyzing experimental NMR data, supporting organic molecules, RNA, proteins, sugars, DNA, and many other biomolecules.

relax supports several NMR theories, implements various data analysis tools as modular components, and it can interface with other programs, such as Dasha and Modelfree. It supports a wide range of NMR theories, incorporates several data analysis tools, allows users to visualize data, as well as to interact with other programs.

Despite the fact that the application comes with both a CLI (Command-line Interface) and GUI (Graphical User Interface) front-end, several third-party graphical user interfaces (GUIs) exist for relax.

Among the supported types of analyzes, relax can handle relaxation dispersion, consistency testing of multiple field NMR (Nuclear Magnetic Resonance) relaxation data, N-state model and frame order, model-free analysis, R1 and R2, NOE, RSDM (Reduced Spectral Density Mapping), as well as stereochemistry investigations.

In order to automate the data analysis process, it is possible to create very complex scripts by using building blocks. For this, the developers provide various sample scripts that will help you to understand the script construction and to more easily create your own.

Looking under the hood, we can notice that the program is written entirely in the Python programming language and uses the cross-platform Qt GUI toolkit for its graphical user interface, which means it runs on Linux, Microsoft Windows and Mac OS X operating systems.

The application is available for download as binary archives for many GNU/Linux operating systems, supporting both 32-bit (x86) and 64-bit (x86_64) instruction set architectures, as well as a source tarball.