Ollama (Local LLMs)

Run local LLMs with Ollama using the OpenAI-compatible API.

Prerequisites

1. Install Ollama from https://ollama.ai
2. Pull a model: ollama pull llama3 or ollama pull gemma2
3. Ensure Ollama is running (default: http://localhost:11434)

Usage

Ollama exposes an OpenAI-compatible API, so use the :openai provider with a custom base_url:

# Create a model struct for your Ollama model
{:ok, model} = ReqLLM.model(%{id: "llama3", provider: :openai})

# Generate text with custom base_url
{:ok, response} = ReqLLM.generate_text(model, "Hello!", base_url: "http://localhost:11434/v1")

Streaming

{:ok, model} = ReqLLM.model(%{id: "gemma2", provider: :openai})

{:ok, stream} = ReqLLM.stream_text(model, "Write a haiku", base_url: "http://localhost:11434/v1")

for chunk <- stream do
  IO.write(chunk.text || "")
end

Helper Module

For convenience, create a wrapper module:

defmodule MyApp.Ollama do
  @base_url "http://localhost:11434/v1"

  def generate_text(model_name, prompt, opts \\ []) do
    {:ok, model} = ReqLLM.model(%{id: model_name, provider: :openai})
    ReqLLM.generate_text(model, prompt, Keyword.put(opts, :base_url, @base_url))
  end

  def stream_text(model_name, prompt, opts \\ []) do
    {:ok, model} = ReqLLM.model(%{id: model_name, provider: :openai})
    ReqLLM.stream_text(model, prompt, Keyword.put(opts, :base_url, @base_url))
  end
end

# Usage
MyApp.Ollama.generate_text("llama3", "Explain pattern matching")
MyApp.Ollama.generate_text("gemma2", "Write a poem", temperature: 0.9)

Common Models

Troubleshooting

• Connection refused: Ensure Ollama is running (ollama serve)
• Model not found: Pull the model first (ollama pull <model>)
• Slow responses: First request loads model into memory; subsequent requests are faster
• Custom host: Set OLLAMA_HOST environment variable or use different base_url

Resources

• Ollama Documentation
• Available Models