> For clean Markdown of any page, append .md to the page URL.
> For a complete documentation index, see https://docs.nvidia.com/nemo/guardrails/llms.txt.
> For full documentation content, see https://docs.nvidia.com/nemo/guardrails/llms-full.txt.
> For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://docs.nvidia.com/nemo/guardrails/_mcp/server.

# Getting Started with Colang 2.0

> Build Colang 2.0 guardrails step by step, from Hello World to LLM and multimodal flows.

<a id="getting_started" />

This section is a getting started guide for Colang 2.0. It starts with a basic "Hello World" example and then goes into dialog rails, input rails, multimodal rails, and other Colang 2.0 concepts like interaction loops and LLM flows. This guide does not assume any experience with Colang 1.0, and all the concepts are explained from scratch.

## Prerequisites

This getting started guide will focus only on the Colang files. For complete details on how to install NeMo Guardrails and create a sample configuration, refer to the [Installation Guide](/get-started/installation-guide) and the [NeMo Guardrails Getting Started Guide](/get-started/integrate-into-application).

The `config.yml` file for all the examples should have the following content:

**config.yml**

```yaml
colang_version: "2.x"

models:
  - type: main
    engine: openai
    model: gpt-4-turbo
```

The above config sets the Colang version to "2.x" (this is needed since "1.0" is currently the default) and the LLM engine to OpenAI's `gpt-4-turbo`. Make sure to set the required API access key as an environment variable (e.g. OPENAI\_API\_KEY for OpenAI API). See section [Supported Models](../language-reference/make-use-of-llms#make-use-of-llms-supported-models) for all supported models.

Check the section [Development and Debugging](../language-reference/development-and-debugging#development-and-debugging) for how you can install Colang syntax highlighting to make editing Colang scripts easier.

## Terminology

At a high level, Colang adopts as much as possible from the Python terminology. This guide will talk about Colang scripts and modules (i.e., `.co` files), packages (i.e., folders), standard library, importing mechanism, etc.

## Guides

Create the first Colang 2.0 flow.

Add dialog rails with LLM integration.

Use multimodal events and actions.

Add input rails to inspect and block user input.

Build a simple interaction loop.

Let the LLM generate flow continuations.

Choose what to learn after the getting started guide.