Different software solutions have been developed for the calculation and implementation of ambisonic decoding matrices. The present paper presents and describes a new data file format which can be used as an intermediate between solutions. Currently available software solutions use particular data conventions causing difficult compatibility and exchangeability. In the present work an open-source toolkit is developed for storing, handling and using ambisonic decoding matrices. The toolkit includes tools for conversion from common matrix data conventions to the ADD-format and back, calculating decoding matrices, decoding ambisonic signals and extracting existing matrices from external decoding tools. The new ADD-format and toolkit enables increased flexibility in production workflows and eliminates the drawbacks and limitations regarding compatibility between software solutions.