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

# OpenRouter Provider

> Access 200+ AI models through a single API

OpenRouter is an AI model aggregator that provides unified access to 200+ models from OpenAI, Anthropic, Google, Meta, Mistral, and many others.

## Configuration

<ParamField path="provider" type="string" required>
  Set to `"openrouter"`
</ParamField>

<ParamField path="api_key" type="string" required>
  OpenRouter API key. Get yours at [openrouter.ai/keys](https://openrouter.ai/keys)
</ParamField>

<ParamField path="model" type="string" required>
  Fully qualified model name in format `provider/organization/model-name`
</ParamField>

<ParamField path="temperature" type="number">
  Sampling temperature (0.0-2.0). Defaults to `0.7`.
</ParamField>

<ParamField path="max_tokens" type="number">
  Maximum output tokens.
</ParamField>

## Example Configuration

```json theme={null}
{
  "provider": "openrouter",
  "model": "openrouter/anthropic/claude-sonnet-4",
  "api_key": "sk-or-v1-...",
  "temperature": 0.7
}
```

## Model Selection

OpenRouter uses fully qualified model names:

* `openrouter/anthropic/claude-sonnet-4`
* `openrouter/openai/gpt-4o`
* `openrouter/google/gemini-2.0-flash`
* `openrouter/meta-llama/llama-3.2-90b-vision`
* `openrouter/mistralai/mistral-large-2411`

Browse available models at [openrouter.ai/models](https://openrouter.ai/models)

## Authentication

OpenRouter uses Bearer token authentication with additional headers:

```
Authorization: Bearer sk-or-v1-...
HTTP-Referer: https://github.com/nullclaw/nullclaw
X-Title: nullclaw
```

The `HTTP-Referer` and `X-Title` headers are automatically added by the provider.

## Capabilities

| Feature          | Support               |
| ---------------- | --------------------- |
| Streaming        | Yes                   |
| Function Calling | Yes (model-dependent) |
| Vision (images)  | Yes (model-dependent) |
| System Messages  | Yes                   |
| Tool Calls       | Yes                   |

## Reasoning Models

OpenRouter supports OpenAI reasoning models (o1, o3, gpt-5):

```json theme={null}
{
  "provider": "openrouter",
  "model": "openrouter/openai/o3-mini",
  "api_key": "sk-or-v1-...",
  "max_tokens": 100,
  "reasoning_effort": "medium"
}
```

* Temperature is automatically omitted for reasoning models
* Uses `max_completion_tokens` field
* Supports `reasoning_effort` parameter

## Warmup

OpenRouter provider includes a warmup feature to pre-establish TLS connections:

```zig theme={null}
pub fn warmup(self: *OpenRouterProvider) void {
    const api_key = self.api_key orelse return;
    // Hit auth endpoint to warm up connection
    const resp = curlGet(self.allocator, WARMUP_URL, auth_hdr) catch return;
    self.allocator.free(resp);
}
```

The warmup hits `https://openrouter.ai/api/v1/auth/key` to establish a connection.

## Code Example

From `src/providers/openrouter.zig`:

```zig theme={null}
pub const OpenRouterProvider = struct {
    api_key: ?[]const u8,
    allocator: std.mem.Allocator,

    const BASE_URL = "https://openrouter.ai/api/v1/chat/completions";
    const WARMUP_URL = "https://openrouter.ai/api/v1/auth/key";
    const REFERER = "https://github.com/nullclaw/nullclaw";
    const TITLE = "nullclaw";

    pub fn init(allocator: std.mem.Allocator, api_key: ?[]const u8) OpenRouterProvider {
        return .{
            .api_key = api_key,
            .allocator = allocator,
        };
    }
};
```

## Multi-Turn Conversations

OpenRouter supports full conversation history:

```json theme={null}
{
  "model": "openrouter/anthropic/claude-sonnet-4",
  "messages": [
    {"role": "system", "content": "You are a helpful assistant"},
    {"role": "user", "content": "Hello"},
    {"role": "assistant", "content": "Hi! How can I help?"},
    {"role": "user", "content": "What's 2+2?"}
  ]
}
```

## Error Handling

The provider classifies common OpenRouter API errors:

* `error.RateLimited` — 429 rate limit exceeded
* `error.ContextLengthExceeded` — Context window too large
* `error.InvalidApiKey` — Authentication failed
* `error.ApiError` — Generic API error
* `error.NoResponseContent` — Empty response

## Pricing

OpenRouter charges based on the model you use. Pricing varies by model:

* Check current pricing at [openrouter.ai/models](https://openrouter.ai/models)
* Set spending limits in your OpenRouter dashboard
* Monitor usage at [openrouter.ai/activity](https://openrouter.ai/activity)

## Related

* [Providers Overview](/providers/overview)
* [OpenAI Provider](/providers/openai)
* [Anthropic Provider](/providers/anthropic)