> ## Documentation Index
> Fetch the complete documentation index at: https://langwatch.ai/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Langy Supported Models and Providers

> Reference table of the model providers Langy can use, how each is configured, and the model roles that pick which model runs where.

Langy runs on the model providers your project has enabled. Every provider except Codex is configured with an API key you paste in model-provider settings; Codex is configured by signing in with your OpenAI account over OAuth. Langy sends all model traffic through the LangWatch AI Gateway, so tracing, rate limits, budgets, and model policy apply to every call.

## Providers

| Provider         | How you configure it                                 | Notes                                                                                                                                 |
| ---------------- | ---------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------- |
| OpenAI           | API key                                              | `gpt-5.6` family and others.                                                                                                          |
| Anthropic        | API key                                              | `claude-opus-4-8` family and others.                                                                                                  |
| Codex            | Sign in with your OpenAI account (OAuth device code) | The only provider you connect by signing in, not by pasting a key. Restricted to the Langy and Fast roles. See [Codex](/docs/langy/codex). |
| Gemini           | API key                                              |                                                                                                                                       |
| Azure OpenAI     | API key                                              |                                                                                                                                       |
| Amazon Bedrock   | API key or credentials                               |                                                                                                                                       |
| Google Vertex    | API key or credentials                               |                                                                                                                                       |
| DeepSeek         | API key                                              |                                                                                                                                       |
| xAI              | API key                                              |                                                                                                                                       |
| Cerebras         | API key                                              |                                                                                                                                       |
| Groq             | API key                                              |                                                                                                                                       |
| Voyage           | API key                                              | Embeddings.                                                                                                                           |
| Custom (LiteLLM) | API key or endpoint                                  | Any provider reachable through LiteLLM.                                                                                               |

You add these in model-provider settings, the same drawer the rest of LangWatch uses. Keys are stored encrypted at rest. See [Models and bring your own key](/docs/langy/models).

## Model roles

A role decides which configured model runs for a given kind of work. Langy uses four roles.

| Role       | What it drives                               |
| ---------- | -------------------------------------------- |
| Default    | The general-purpose model for standard work. |
| Fast       | Lighter, quicker assists.                    |
| Langy      | Langy's own chat and coding model.           |
| Embeddings | Vector embeddings.                           |

## The model picker

In the Langy composer the picker shows a short shortlist by default, then a **More models** disclosure with the rest of the models your enabled providers expose.

* The shortlist is **derived, not fixed**. It starts with the Langy default, then your current selection, then one representative each of the quick, balanced, and reasoning capability groups. It is not a hardcoded list of names.
* The **More models** count is **data-driven per project**. It is however many other models your enabled providers make available, so it differs between projects.

Named model families you will see when the matching provider is enabled include `gpt-5.6-terra` (the default), `gpt-5.6-sol`, `gpt-5.6-luna` (fast), and `claude-opus-4-8`.

<Note>
  Codex models appear in the picker only for the Langy and Fast roles. OpenAI's terms scope the Codex subscription path to coding-assistant harnesses and light AI assists, so Codex is offered for Langy and Fast but not for the playground, evaluations, or workflows. See [Codex](/docs/langy/codex).
</Note>

## Bring your own key

Every provider except Codex is bring-your-own-key: you paste your own API key and Langy runs on your account. There is no LangWatch-provided default key for Langy models. For who pays and how to see the spend, see [Token usage and cost](/docs/langy/token-usage-and-cost).

<Info>
  **Also check:** [Models and bring your own key](/docs/langy/models), [Codex](/docs/langy/codex), [Token usage and cost](/docs/langy/token-usage-and-cost).
</Info>

## Reference

* [Models and bring your own key](/docs/langy/models)
* [Codex](/docs/langy/codex)
* [Limits](/docs/langy/reference/limits)