Ollama is the model runtime
Ollama manages model downloads, local execution and a programmatic API. Its resource needs are dominated by the model selected for inference.
Open WebUI is the application layer
Open WebUI adds browser-based conversations, user management and application data. It connects to Ollama or other compatible backends rather than replacing the model runtime.
Common deployment patterns
- One host for both services: simple for personal evaluation, but model load and application traffic share resources.
- Separate application and inference hosts: easier to isolate security and scale components independently.
- Hosted model API plus Open WebUI: avoids local model hardware but introduces provider cost and data-policy considerations.
Security boundary
Keep the raw Ollama API private. Expose Open WebUI through HTTPS, control registration and use stable secrets and persistent storage. Install the runtime with the Ollama Linux guide, then add the interface with the Open WebUI Docker guide.