OpenChat is an open-source Python framework that makes it trivially easy to chat with neural dialogue models: it wraps more than 40 open conversational models behind a single class you can start interacting with in one line of code. The project is hosted on GitHub with around 430 stars; development was most active in the early 2020s, with the last updates in 2023.
When OpenChat appeared, every research group released dialogue models with different tokenizers, weights and inference scripts, making comparison painful. The framework normalises that: install it from PyPI, instantiate OpenChat with a model name, and you can converse with models such as GPT-Neo in several sizes, BlenderBot, DialoGPT and many other community checkpoints without writing loading or generation code. Under the hood it handles model download, tokenization and decoding consistently, so swapping the model is a one-word change — handy for coursework, demos and quick qualitative comparisons of open chat models. It predates the instruction-tuned LLM era, so the models are classic research checkpoints rather than modern assistants, but as a lightweight playground and teaching tool it remains a neat snapshot of open dialogue research.
Because every model is driven through the same loop, the framework also serves as a gentle introduction to how neural dialogue systems work internally — tokenization, context handling and decoding strategies included. Its model zoo doubles as a compact catalogue of the open conversational models that defined the pre-ChatGPT research era, all reachable from one small codebase.
OpenChat is completely free and open source under the Apache-2.0 license. Models run locally, so there are no API fees either.
Students, educators and NLP hobbyists who want to explore and compare classic open-source dialogue models with minimal setup.