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

# API Gateway & Router Service

> Use Alter as an OpenAI-compatible API endpoint for model routing

Alter provides an OpenAI-compatible endpoint you can use as a single Router across providers.

<Warning>
  **Intended use:** API Router is for personal usage, lightweight utilities, and low-volume projects. It is **not** intended to run high-throughput agentic systems (for example code agents, OpenClaw-style systems) or production services for other users.
</Warning>

## What you get

* One endpoint for many model providers
* Centralized billing through Alter
* `Provider#Model-name` model IDs
* Compatibility with OpenAI-style tools and SDKs

## Quick setup

### 1) Generate an API key

1. Open Alter Settings (`⌘ ,`)
2. Go to **Router**
3. Under **Alter API Keys**, click **Add New Key**
4. Copy the key (`sk-...`)

### 2) Use the endpoint

Primary endpoint:

```text theme={null}
https://alterhq.com/api
```

Some clients require `/v1`:

```text theme={null}
https://alterhq.com/api/v1
```

### 3) List available models

```bash theme={null}
curl https://alterhq.com/api/models \
  -H "Authorization: Bearer YOUR_API_KEY"
```

## Model naming format

Use this format when selecting a model:

```text theme={null}
Provider#Model-name
```

Examples:

* `OpenAI#gpt-5`
* `Claude#claude-sonnet-4-6`
* `Gemini#gemini-2.5-pro`
* `Alter#best`

## Split guides

To keep this page focused, advanced topics are in dedicated guides:

* [API Router for Development](/api-router/development)
* [API Router Operations & Troubleshooting](/api-router/operations)
* [App Integrations with API Router](/api-router/app-integrations)
* [Set Up TypingMind with Alter API](/api-router/typingmind)

## Related Docs

* [API Router Overview](/references/api-router-overview)
* [API Model Reference](/references/api-model-names)
* [Settings - Router](/how-to/settings-guide#router-settings)
* [Settings - API Keys](/how-to/settings-guide#api-keys-settings)