Stateful Chats

The /api/v1/chat endpoint is stateful by default. This means you don't need to pass the full conversation history in every request — LM Studio automatically stores and manages the context for you.

How it works

When you send a chat request, LM Studio stores the conversation in a chat thread and returns a response_id in the response. Use this response_id in subsequent requests to continue the conversation.

curl http://localhost:1234/api/v1/chat \
  -H "Authorization: Bearer $LM_API_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "ibm/granite-4-micro",
    "input": "My favorite color is blue."
  }'

The response includes a response_id:

{
  "model_instance_id": "ibm/granite-4-micro",
  "output": [
    {
      "type": "message",
      "content": "That's great! Blue is a beautiful color..."
    }
  ],
  "response_id": "resp_abc123xyz..."
}

Continue a conversation

Pass the previous_response_id in your next request to continue the conversation. The model will remember the previous context.

curl http://localhost:1234/api/v1/chat \
  -H "Authorization: Bearer $LM_API_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "ibm/granite-4-micro",
    "input": "What color did I just mention?",
    "previous_response_id": "resp_abc123xyz..."
  }'

The model can reference the previous message without you needing to resend it and will return a new response_id for further continuation.

Disable stateful storage

If you don't want to store the conversation, set store to false. The response will not include a response_id.

curl http://localhost:1234/api/v1/chat \
  -H "Authorization: Bearer $LM_API_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "ibm/granite-4-micro",
    "input": "Tell me a joke.",
    "store": false
  }'

This is useful for one-off requests where you don't need to maintain context.