MORTAR was implemented as a rich client application based on Java 17 using Adoptium OpenJDK . Gradle was used to facilitate the build process and the integration of further libraries. All libraries used are obtained from the Maven Central Repository . More memory-intensive properties, such as the 2D structure image, are only created when needed and then released afterwards for the Java garbage collector to discard. Similarly, the central CDK data structure for the representation of chemical molecules, IAtomContainer, is only created on demand from the SMILES representation of a molecule or fragment. SMILES line notations are internally used as the only retained molecular structure information to save memory. This is useful when loading large molecule sets and allows working on less powerful computer systems. This way, MORTAR is able to import the complete COCONUT database with more than 400,000 natural products on a standard laptop with only 16 GB RAM.