There are millions of species of bacteria1, few of which are well characterized. However, these non-model organisms perform cellular processes and are native to harsh biomes, and this makes them of great interest to researchers2. Synthetic biologists take great interest in engineering such bacteria, in an attempt to harness their natural abilities3. Because finding the best way to genetically modify an organism can be a laborious and resource-demanding process, we have developed a kit of modular plasmids, designed to quickly test multiple broad host range origins of replication (ORIs). To do this, we used a cloning technique called Golden Gate Assembly to build plasmids. Golden Gate Assembly uses Type IIs restriction enzymes, which allows researchers to pick the overhang each cut produces. Therefore, many parts can be assembled together at once, in a specific order. The plasmids are minimal and standardized4. They include barcode sequences and reporter genes to indicate which plasmid is which. A mixture of all the plasmids is transformed into a single sample of host bacteria, and the colored reporters allow the researcher to quickly determine which ORIs allow the host to replicate the plasmid.