Build Your First Local AI App with the Ollama API

Confirm that the server and model work with curl before adding a framework. The local and cloud API base URLs are different, so verify that sensitive prompts point to localhost.

curl http://localhost:11434/api/generate -d '{
  "model": "gemma3:4b",
  "prompt": "Explain local AI in one sentence.",
  "stream": false
}'

The chat endpoint accepts role-based messages. Your application should send the history required for each request rather than assuming the server remembers every conversation.

Summarize old turns or begin a new session when context becomes unnecessarily long.

Streaming improves perceived latency but requires the client to assemble chunks, handle cancellation, and surface mid-stream failures.

Begin with a complete non-streaming response, validate the shape, and add streaming only when the basic flow is reliable.

Structured Outputs can constrain a response with a JSON schema. A lower temperature can improve repeatability.

Still validate parsing, required fields, value ranges, and factual claims against the source data.

• Define required fields
• Limit retries
• Validate ranges and lengths
• Log validation errors without storing sensitive prompts
• Provide a human-review path

Handle a stopped server, missing model, timeout, oversized request, user cancellation, and invalid JSON. Do not retry indefinitely.

Keep the server on localhost unless you have designed authentication, TLS, access controls, monitoring, and rate limits.