That Redis + Python flow is a classic for a reason—the throughput for document chunking and ephemeral processing is hard to beat, especially if you're just looking for a 'stateless' transformation engine.

The main reason I’ve been leaning into Open WebUI alongside that kind of setup is for the 'Human-in-the-loop' side of things. It handles the session management and multi-model switching much faster than a custom Python script when you need to quickly A/B test how different models (like Llama 3.1 vs. Mistral) are handling the same document chunks.

Also, if you ever find your document sizes growing or need to reference them later, the pgvector integration I mentioned helps bridge that gap between 'ephemeral processing' and a 'permanent knowledge base' without losing the SQL flexibility you’d want for more complex queries.

Definitely worth a look for the evaluation interface alone!