OpenAI provides hosted, pay-per-token access to models like GPT through its API and the ChatGPT product, with no option to self-host the underlying models or inspect their weights. Teams that need to run inference on their own infrastructure — for data privacy, cost control at scale, or to avoid dependence on a single API provider — look at open-source platforms that let them bring their own models instead.
Dify is the closest match here: an open-source LLM app platform with visual workflow building, RAG, and agent support that can connect to 100+ models, including self-hosted open-weight models, instead of being locked to one provider.
FAQ
Is there a free, open-source alternative to OpenAI?
Yes, for the application layer. Dify is open source and free to self-host, and can connect to open-weight models you run yourself instead of OpenAI's hosted API.
What's the best open-source alternative to OpenAI?
Dify is the standout option if you want a visual platform for building LLM apps and agents on top of models you control, rather than being tied to OpenAI's hosted API.
What are the top open-source alternatives to OpenAI?
Browse all open-source alternatives to OpenAI above, or explore the full Developer Tools category for more options.