I do exactly this, use LiteLLM to bridge it. In fact I use LiteLLM to bridge OpenAI and Groq too. Even though OpenWebUI supports them directly, with LiteLLM I can control better which models I see. Otherwise my model list gets cluttered up. I configured this back when OpenWebUI only supported one OpenAI endpoint but I kept using it because it's just quite handy.
And no it doesn't cost extra credits, isn't ignored and doesn't have hardcoded context length. It works perfectly.
Also, it's pretty easy to find unresolved bugs related to openwebui not handling context length parameters correctly - I believe I actually read something from the author saying that this parameter is effectively disabled (for non-local LLMs maybe?).
And no it doesn't cost extra credits, isn't ignored and doesn't have hardcoded context length. It works perfectly.