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

# LangChain managed models

> Call LangChain-managed models through the LLM Gateway with no provider key or account of your own. Authenticate with your LangSmith API key.

<Note>
  **Private beta:** The LLM Gateway is in private [beta](/langsmith/release-stages). APIs and features may change as we iterate. Sign up for [the waitlist](https://www.langchain.com/langsmith-llm-gateway-waitlist) to get access.
</Note>

The `/langchain` provider serves **LangChain-managed models** through the LLM Gateway. With the [other providers](/langsmith/llm-gateway#supported-providers), you bring your own account and key. With managed models, LangChain owns the upstream provider credential, so you can start calling a model immediately with only your [LangSmith API key](/langsmith/create-account-api-key). No [provider secret](/langsmith/llm-gateway-admin-setup#2-add-provider-secrets) setup is required.

<Card title="Base URL" icon="link">
  Point any OpenAI-compatible client at:

  ```text theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
  https://gateway.smith.langchain.com/langchain/v1
  ```

  Authenticate with your LangSmith API key as a bearer token.

  For regional base URLs, see [Regional gateways](/langsmith/llm-gateway#regional-gateways).
</Card>

## Available models

The provider is OpenAI-compatible and advertises branded model IDs. You select a model by name (case-insensitive) in the request body, and the gateway routes it to the managed upstream model.

| Model ID        | Description                                      |
| --------------- | ------------------------------------------------ |
| `LangSmith:pro` | A high-capability general-purpose managed model. |

You can also list the available models programmatically:

```bash theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
curl https://gateway.smith.langchain.com/langchain/v1/models \
    -H "Authorization: Bearer $LANGSMITH_API_KEY"
```

The response is the standard OpenAI `/v1/models` list containing only the managed model IDs above.

## Prerequisites

Before you can call the `/langchain` provider, confirm that:

* Your organization is on a **paid plan** ([Developer, Plus, Startup, or Premier](/langsmith/pricing-plans)).
* You have a workspace-scoped [LangSmith API key](/langsmith/create-account-api-key) attached to a role with `gateway:invoke` and `workspaces:read` [permissions](/langsmith/organization-workspace-operations). See [Admin setup](/langsmith/llm-gateway-admin-setup) if you're unsure.

## Make a call

Point any OpenAI-compatible client at `https://gateway.smith.langchain.com/langchain/v1`, authenticate with your LangSmith API key, and set `model` to one of the advertised model IDs.

<CodeGroup>
  ```bash curl theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
  curl https://gateway.smith.langchain.com/langchain/v1/chat/completions \
      -H "Authorization: Bearer $LANGSMITH_API_KEY" \
      -H "Content-Type: application/json" \
      -d '{"model":"LangSmith:pro","messages":[{"role":"user","content":"ping"}]}'
  ```

  ```python OpenAI SDK theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
  import os

  from openai import OpenAI

  client = OpenAI(
      base_url="https://gateway.smith.langchain.com/langchain/v1",
      api_key=os.environ["LANGSMITH_API_KEY"],
  )
  response = client.chat.completions.create(
      model="LangSmith:pro",
      messages=[{"role": "user", "content": "ping"}],
  )
  print(response.choices[0].message.content)
  ```

  ```python LangChain theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
  import os

  from langchain.chat_models import init_chat_model

  model = init_chat_model(
      model="LangSmith:pro",
      model_provider="openai",
      base_url="https://gateway.smith.langchain.com/langchain/v1",
      api_key=os.environ["LANGSMITH_API_KEY"],
  )
  print(model.invoke("ping").content)
  ```
</CodeGroup>

## Supported endpoints

The `/langchain` provider forwards two OpenAI-compatible prompt endpoints and serves the model list locally:

| Method & path                         | Behavior                               |
| ------------------------------------- | -------------------------------------- |
| `POST /langchain/v1/chat/completions` | Chat completions, including streaming. |
| `POST /langchain/v1/responses`        | OpenAI Responses API.                  |
| `GET /langchain/v1/models`            | Lists the managed model IDs.           |

Any other path returns `404`. A request for a model that isn't advertised also returns `404` with a message listing the available model IDs.

## Pricing

Invocations will be billed to your account.

Standard gateway [spend policies](/langsmith/llm-gateway-spend-policies) still apply on top of the managed-model cap, so you can add tighter per-key or per-user limits.

## Tracing

Like all gateway traffic, managed-model calls are traced to LangSmith. See [Traces, Engine, and access control](/langsmith/llm-gateway-access) for where traces land and how to control access to them.

## Next steps

* [Quickstart](/langsmith/llm-gateway-quickstart): make your first gateway-proxied call.
* [Spend policies](/langsmith/llm-gateway-spend-policies): add cost limits on top of the managed-model cap.
* [Custom model providers](/langsmith/llm-gateway-custom-providers): route to your own OpenAI-compatible endpoints.

***

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