Integration with external RAG pipelines

[anmolbhatia05]

Is your feature request related to a problem? Please describe.
Our company has a lot of internal documents stored in a vector DB, system prompt that works well with our retrieval use cases and return prompt templates, we would like to use open-webui as a frontend to this RAG system.

Describe the solution you'd like
It would make this tool really extensible if there is a way to integrate existing RAG pipelines that have their own embeddings store, system prompts, prompt templates, etc.

Describe alternatives you've considered
We made our own frontend, but open-webui has so many other functionalities that we would like to somehow integrate these.

Additional context
Add any other context or screenshots about the feature request here.

[tjbck]

#3687 (comment)