> ## Documentation Index
> Fetch the complete documentation index at: https://exa.ai/docs/llms.txt
> Use this file to discover all available pages before exploring further.
# OpenRouter
> Ground any OpenRouter model with Exa web search through the openrouter:web_search server tool.
Exa is the search engine behind [OpenRouter](https://openrouter.ai)'s web search. OpenRouter gives you one API for hundreds of models, and Exa gives those models live web access: any model without native search grounds through Exa by default, and any model can be pointed at Exa explicitly. No Exa API key is needed. OpenRouter runs the searches server-side and bills them to your OpenRouter credits.
## Use the web search server tool
Add `openrouter:web_search` to your `tools` array and the model decides when to search, what to search for, and whether to search again within the same request. [Server tools](https://openrouter.ai/docs/guides/features/server-tools/web-search) are in beta on OpenRouter, and they replace the deprecated `web` plugin and `:online` model variants; see OpenRouter's [migration guide](https://openrouter.ai/docs/guides/features/server-tools/web-search#migrating-from-the-web-search-plugin) if you use either.
```javascript JavaScript theme={null}
const response = await fetch("https://openrouter.ai/api/v1/chat/completions", {
method: "POST",
headers: {
Authorization: "Bearer ",
"Content-Type": "application/json",
},
body: JSON.stringify({
model: "openai/gpt-5.2",
messages: [
{ role: "user", content: "What were the major AI announcements this week?" },
],
tools: [{ type: "openrouter:web_search" }],
}),
});
const data = await response.json();
console.log(data.choices[0].message.content);
```
```python Python theme={null}
import requests
response = requests.post(
"https://openrouter.ai/api/v1/chat/completions",
headers={
"Authorization": "Bearer ",
"Content-Type": "application/json",
},
json={
"model": "openai/gpt-5.2",
"messages": [
{"role": "user", "content": "What were the major AI announcements this week?"}
],
"tools": [{"type": "openrouter:web_search"}],
},
)
print(response.json()["choices"][0]["message"]["content"])
```
```bash cURL theme={null}
curl https://openrouter.ai/api/v1/chat/completions \
-H "Authorization: Bearer " \
-H "Content-Type: application/json" \
-d '{
"model": "openai/gpt-5.2",
"messages": [
{ "role": "user", "content": "What were the major AI announcements this week?" }
],
"tools": [{ "type": "openrouter:web_search" }]
}'
```
With the default `engine: "auto"`, OpenRouter uses the provider's native search where a model has one and Exa everywhere else. Set `engine: "exa"` to keep one search behavior across every model:
```json theme={null}
{
"type": "openrouter:web_search",
"parameters": {
"engine": "exa",
"mode": "auto",
"max_results": 5,
"max_total_results": 20,
"allowed_domains": ["arxiv.org"],
"excluded_domains": ["reddit.com"]
}
}
```
| Parameter | Use it to |
| ------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| `mode` | Trade latency for depth: `instant`, `fast`, `auto` (default), `deep-lite`, `deep`, or `deep-reasoning`. The modes map to Exa's [search types](/docs/search/quickstart). |
| `max_results` | Cap results per search call (default 5) |
| `max_uses` | Cap how many times the model may search in one request |
| `max_total_results` | Cap cumulative results across all searches in one request |
| `max_characters` | Set an exact per-result character budget for highlights |
| `search_context_size` | Use a preset budget instead: `low`, `medium`, or `high` |
| `allowed_domains`, `excluded_domains` | Filter result domains. Exa supports both filters in the same request. |
## How results come back
OpenRouter requests [Exa highlights](/docs/search/highlights) for each result rather than full page text: extractive excerpts sized adaptively, typically 2,000 to 4,000 characters per result, unless you set `max_characters` or `search_context_size`. The model reads the excerpts, and API callers receive them in standardized `url_citation` annotations on the response message. Within one result, `[...]` markers separate excerpts drawn from different parts of the page.
## Pricing
Exa searches bill to your OpenRouter credits, in addition to the model's token costs for reading the results. The `instant`, `fast`, and `auto` modes cost \$0.007 per search, `deep-lite` and `deep` cost \$0.012, and `deep-reasoning` costs \$0.015. Each search includes up to 10 results, and additional results cost \$0.001 each. See [OpenRouter's web search docs](https://openrouter.ai/docs/guides/features/server-tools/web-search) for current rates.
The response's `usage` object reports how many searches the model ran in `server_tool_use.web_search_requests`.
## Resources
Full configuration reference for `openrouter:web_search`.
How OpenRouter gives hundreds of models web search with Exa.