Open WebUI is a self-hosted, ChatGPT-style interface. As long as a serving API is OpenAI-compatible, you can point a local Open WebUI instance at a cloud endpoint and chat with models like Apertus. This is a friendly UI that lets you chat with your models without needing to know the details of the API. It is also a popular choice for institutions and small to medium-sized teams.

Please visit the official guide for further details. On this page we provide some advice for configuring this product to work well with our models.

1. Get your API key

Your Apertus provider (see our Getting Started page) will have a method of generating an API key to connect with the model. They will also provide you with a URL through which models can be accessed. This is usually an OpenAI-compatible service with a v1 at the end. Set this up as environment variables with these commands on the terminal or launch script:

export APERTUS_SERVING_KEY="sk-rc-..."           # your key from an API key page
export APERTUS_SERVING_URL="https://api.../v1"   # link to your API endpoint

2. Run Open WebUI with Docker

The quickest path is to bake the connection details straight into the docker run command:

docker run -d\
  -p 3000:8080\
  -e OPENAI_API_BASE_URL=$APERTUS_SERVING_URL\
  -e OPENAI_API_KEY=$APERTUS_SERVING_KEY\
  -v open-webui:/app/backend/data\
  --name open-webui\
  --restart always\
  ghcr.io/open-webui/open-webui:main
  • -p 3000:8080 exposes the UI on http://localhost:3000.
  • OPENAI_API_BASE_URL points Open WebUI at our OpenAI-compatible endpoint.
  • OPENAI_API_KEY authenticates every request with your key.
  • -v open-webui:/app/backend/data keeps your accounts, chats, and settings across restarts.

Then open http://localhost:3000, create a local admin account (this stays on your machine), and start chatting.

3. (Optional) Configure the connection from the UI instead

If you’d rather not put the key in the docker run command, start the container without the two -e flags and add the connection from the UI:

  1. Go to Settings → Admin Settings → Connections.
  2. Under OpenAI API, set:
    • API Base URL: https://..../v1
    • API Key: your secret key
  3. Save. Our models will now appear in the model picker.

4. Pick a model

Open WebUI auto-discovers everything served at GET /v1/models. Select one from the dropdown, for example:

  • swiss-ai/Apertus-70B-Instruct-2509
  • swiss-ai/Apertus-8B-Instruct-2509

The available list changes over time — the model picker always reflects what’s live. You can also see the full list any time with:

curl $APERTUS_SERVING_URL/models\
  -H "Authorization: Bearer $APERTUS_SERVING_KEY"

Verify the endpoint directly

If something isn’t connecting, confirm the API works on its own before debugging Open WebUI:

curl -X POST $APERTUS_SERVING_URL/chat/completions\
  -H "Content-Type: application/json"\
  -H "Authorization: Bearer $APERTUS_SERVING_KEY"\
  -d '{
    "model": "swiss-ai/Apertus-8B-Instruct-2509",
    "messages": [{"role": "user", "content": "Who is Pablo Picasso?"}],
    "stream": false
  }'

That’s it — a fully local UI, our models, your key. 🎉