# Web Search

When using a web-search-enabled model, you can pass the `web_search_options` parameter to control how much search context is retrieved and processed. Models with this capability can dynamically integrate search results into their reasoning process. 

There's a per-request fee applied by these models. Additionally, these models charge based on search context size, which controls how much data is retrieved and processed per query.

### **Web-Search Enabled Models**

These models support built-in web search:

* `openai/gpt-4o-mini-search-preview`
* `openai/gpt-4o-search-preview`
* `perplexity/sonar-pro`
* `perplexity/sonar-reasoning-pro`
* `perplexity/sonar`
* `perplexity/sonar-reasoning` 

### **Search Context Size**

The `search_context_size` setting controls how much information is pulled from search results. Pricing may vary based on the selected level.

| Level    | Description                                        | Use Case                           |
| -------- | -------------------------------------------------- | ---------------------------------- |
| `low`    | Minimal context for basic queries                  | Quick facts, dates, headlines      |
| `medium` | Moderate context with broader information coverage | General knowledge, short summaries |
| `high`   | Extensive search context for deep research         | In-depth topics, analysis, reports |

### **Sample Request**

This example uses `openai/gpt-4o-mini-search-preview` with medium search context to get real-time sports event info:

```bash
curl --location 'https://api.fastrouter.ai/api/v1/chat/completions' \
--header 'Content-Type: application/json' \
--header 'Authorization: Bearer API-KEY' \
--data '{
  "model": "openai/gpt-4o-mini-search-preview",
  "messages": [
    {
      "role": "user",
      "content": "Which teams are playing the UEFA Champions League final?"
    }
  ],
  "stream": false,
  "top_p": 1,
  "temperature": 0,
  "max_completion_tokens": 120,
  "web_search_options": {
    "search_context_size": "medium"
  }
}'
```

### **Enabling Web Search for Any Model**

You can incorporate relevant web search results for *any* model on FastRouter by appending **:online** to the model slug:

```
{
  "model": "openai/gpt-oss-20b:online"
}
```

### **Pricing**

The web plugin uses your FastRouter credits and charges *$5 per 1000 answers*.


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.fastrouter.ai/web-search.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.