AtoM is fully web-based, multilingual, archival description software. It was originally developed by Artefactual Systems Inc and commissioned by the International Council on Archives (ICA) to support that organization’s descriptive standards. Additional seed funding was also provided by UNESCO, the Dutch Archiefschool in Amsterdam, Direction des Archives de France, United Arab Emirates Centre for Documentation and Research and the World Bank Group Archives.

The current iteration of AtoM (2.x) has also been developed by Artefactual Systems, but supported by funding from archival repositories and organizations in Canada and worldwide that sponsored significant upgrades to the functionality of the 1.x version of the software. The software now supports many national and international descriptive standards, including RAD, DACs and the ICA suite.

AtoM has been designed on the open-source model, with the software, source code and supporting documentation made freely available for download and modification. Making the source code freely available is meant to foster collaboration amongst archival repositories by allowing developers to modify and improve the original code and contribute those improvements back freely for the benefit of the entire archival community. All AtoM code is released under a GNU Affero General Public License (A-GPL 3.0). The AtoM documentation is released under the Creative Commons Attribution-ShareAlike license.