Calculate the fitness of single amino acid substitutions on proteins, using zero-shot protein language models from the [ESM](https://huggingface.co/facebook) and [ESMC](https://huggingface.co/collections/biohub/esmc-model-family) families. **UPDATE:** [Biohub](https://biohub.ai)'s [ESMC model family](https://huggingface.co/collections/biohub/esmc-model-family) (trained on UniRef + MGnify + JGI) is now available alongside ESM2 models. **WARNING:** Due to high server traffic, the tool might become slow or unresponsive. In this case, it is recommended to duplicate and clone the space in your personal HuggingFace account by clicking [here](https://huggingface.co/spaces/thaidaev/zsp?duplicate=true). In the top right corner, there are options to run the app locally or clone the repository.