OpenChatKit is an open-source toolkit and model release from Together Computer that provides instruction-tuned language models (including a 20B GPT-NeoXT-derived chat model), a separate moderation model, and a modular retrieval system to incorporate external, up-to-date knowledge into responses. The repository includes training tooling, inference code, pretrained weights, and utilities for model conversion and deployment. Its value lies in offering a reproducible, community-oriented base for building specialized or general-purpose chatbots that can be customized, extended with retrieval from custom data sources, and deployed with common large-model inference techniques (e.g., DeepSpeed, multi-GPU setups). The project is licensed under Apache 2.0 and was developed mainly by Together Computer with community contributions.