# Can I use API

> Can I use returns web feature browser support data, available as a workflow and API.

Can I use (CanIUse) finds a web feature by name and returns its global support and support across eight browsers. Check browser support needs a feature name, such as CSS grid, and uses browser versions labeled current by Can I use.

- Page: https://fous.com/tools/can-i-use
- Handle: `@can-i-use`
- Category: [Developer tools](https://fous.com/tools/category/developer-tools)
- Source website: https://caniuse.com
- Last verified: Sep 29, 2026

## Methods

### Check browser support

Operation `check_browser_support`, version 1. 1 credit per completed call. Failed calls without a completed billing receipt are free; completed work can remain charged if delivery is interrupted.

Find the closest web feature by name and see its global support and support across eight major desktop and mobile browsers. Current browser support follows the versions labeled current by Can I use.

**Input**

| Field | Type | Required | Example | Description |
|---|---|---|---|---|
| `feature` | string | yes | `"WebP"` | Name of the web feature to check, for example CSS grid. |

**Input schema**

```json
{
  "type": "object",
  "required": [
    "feature"
  ],
  "properties": {
    "feature": {
      "type": "string",
      "description": "Name of the web feature to check, for example CSS grid.",
      "examples": [
        "WebP",
        "CSS grid",
        "dialog element"
      ]
    }
  },
  "additionalProperties": false,
  "examples": [
    {
      "feature": "WebP"
    },
    {
      "feature": "CSS grid"
    },
    {
      "feature": "dialog element"
    }
  ]
}
```

**Output**

| Field | Type | Example | Description |
|---|---|---|---|
| `link` | string | `"https://caniuse.com/webp"` |  |
| `browsers` | array |  |  |
| `browsers[].notes` | string or null | `"See also support for subgrids At first full support: There are some bugs with overflow (1356820, 1348857, 1350925)"` |  |
| `browsers[].browser` | string | `"Chrome"` |  |
| `browsers[].current_support` | string | `"supported"` |  |
| `browsers[].first_fully_supported_version` | string or null | `"32"` |  |
| `description` | string | `"Image format (based on the VP8 video format) that supports lossy and lossless compression, as well as animation and alp` |  |
| `feature_key` | string | `"webp"` |  |
| `feature_title` | string | `"WebP image format"` |  |
| `global_full_support_percent` | number | `96.74` |  |
| `global_full_and_partial_support_percent` | number | `96.82` |  |

**Example input**

```json
{
  "feature": "WebP"
}
```

**Example output**

```json
{
  "link": "https://caniuse.com/webp",
  "browsers": [
    {
      "notes": null,
      "browser": "Chrome",
      "current_support": "supported",
      "first_fully_supported_version": "32"
    },
    {
      "notes": null,
      "browser": "Edge",
      "current_support": "supported",
      "first_fully_supported_version": "18"
    },
    {
      "notes": null,
      "browser": "Firefox",
      "current_support": "supported",
      "first_fully_supported_version": "65"
    }
  ],
  "description": "Image format (based on the VP8 video format) that supports lossy and lossless compression, as well as animation and alpha transparency. WebP generally has better compression than JPEG, PNG and GIF and…",
  "feature_key": "webp",
  "feature_title": "WebP image format",
  "global_full_support_percent": 96.74,
  "global_full_and_partial_support_percent": 96.82
}
```

## Quick start

Replace `YOUR_API_KEY` with a Fous API key. To create one, open Developers at the bottom of Fous Studio, turn on Developer mode, then go to API keys (https://app.fous.com/keys). Change the values in `input` to run the same tool on new data.

```bash
curl 'https://api.fous.com/v1/query' \
  --fail-with-body --silent --show-error --max-time 180 \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H 'Content-Type: application/json' \
  --data-raw '{
  "api": "@can-i-use",
  "visibility": "public",
  "operation": "check_browser_support",
  "version": 1,
  "input": {
    "feature": "WebP"
  },
  "response": {
    "format": "json"
  }
}'
```

```python
# Save as fous.py and run with python3 fous.py. No packages needed.
import json
import urllib.error
import urllib.request

api_key = "YOUR_API_KEY"

body = json.loads("{\n  \"api\": \"@can-i-use\",\n  \"visibility\": \"public\",\n  \"operation\": \"check_browser_support\",\n  \"version\": 1,\n  \"input\": {\n    \"feature\": \"WebP\"\n  },\n  \"response\": {\n    \"format\": \"json\"\n  }\n}")
request = urllib.request.Request(
    "https://api.fous.com/v1/query",
    data=json.dumps(body).encode("utf-8"),
    headers={
        "Authorization": f"Bearer {api_key}",
        "Content-Type": "application/json",
    },
    method="POST",
)
try:
    with urllib.request.urlopen(request, timeout=180) as response:
        result = json.load(response)
except urllib.error.HTTPError as error:
    raise RuntimeError(f"HTTP {error.code}: {error.read().decode('utf-8', errors='replace')}") from error
if result.get("success") is False:
    raise RuntimeError(result.get("error", {}).get("message", "Request failed"))
print(json.dumps(result["data"]["output"], indent=2))
```

```typescript
// Save as fous.mts and run with npx tsx fous.mts.
const apiKey = "YOUR_API_KEY";

const response = await fetch("https://api.fous.com/v1/query", {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${apiKey}`,
    "Content-Type": "application/json",
  },
  signal: AbortSignal.timeout(180_000),
  body: JSON.stringify({
  "api": "@can-i-use",
  "visibility": "public",
  "operation": "check_browser_support",
  "version": 1,
  "input": {
    "feature": "WebP"
  },
  "response": {
    "format": "json"
  }
}),
});
type ApiResult = { success: boolean; data?: { output: unknown }; error?: { message: string } };
const result: ApiResult = await response.json();
if (!response.ok || result.success === false) {
  throw new Error(result.error?.message ?? `HTTP ${response.status}`);
}
if (!result.data) throw new Error("Missing API response data");
console.log(result.data.output);
```

## Use from an AI assistant

Connect this tool to Claude Code, Claude Desktop, Cursor, VS Code, Codex and any MCP client as its own MCP server. Each method is a typed tool whose arguments are the method’s input.

- Server URL: `https://api.fous.com/mcp/tools/can-i-use`
- Authorization: `Authorization: Bearer <Fous API key>`

**Tools**

- `check_browser_support`: Check browser support. 1 credit per completed call. Failed calls without a completed billing receipt are free; completed work can remain charged if delivery is interrupted.
- `fous_get_run`: the result of a run that was still going, by its `request_id`. Free.

Claude Code:

```bash
claude mcp add --scope user --transport http fous-can-i-use https://api.fous.com/mcp/tools/can-i-use --header "Authorization: Bearer ${FOUS_API_KEY:?Set FOUS_API_KEY to your Fous API key}"
```

To give the assistant every tool, connect `https://api.fous.com/mcp`: it finds one with `fous_search_tools` and runs it with `fous_run_tool`. Setup for other clients: https://fous.com/llms-full.txt.

## Use cases

- Check whether a web feature is supported across browsers
- Compare global full and partial support for a feature
- Find the first fully supported version for each browser
- Review browser-specific support notes

## FAQ

### Can I run it with my own inputs?

Yes. Change the inputs in Studio and press Run, or send new inputs from your code, or ask a connected AI assistant.

### Can I call this Can I use tool as an API?

Yes. Send a POST request to /v1/query with your Fous API key and the inputs, and get JSON back.

### How much does it cost?

Each completed run costs 1 credit. Failed runs without a completed receipt are free; completed work can remain charged if delivery is interrupted. With pay as you go, a credit costs 1¢. Monthly plans cost less per credit.

### Do I need a Can I use account?

No. You only need a Fous account.

### How current is the data?

Fous gets the data from caniuse.com when you run it. Some results are reused for up to 24 hours, and results that use your account or key are never reused. It was last verified on Sep 29, 2026.

### Which browsers support a web feature?

Check browser support returns support data across eight major desktop and mobile browsers.

### What is a feature’s global support?

Check browser support returns global full support and global full and partial support percentages.

### Which browser version first fully supports a feature?

Check browser support returns the first fully supported version for each browser.

## Related

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- [VS Code Marketplace API](https://fous.com/tools/vs-code-marketplace.md): Public listings for Visual Studio Code extensions.
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- [ICANN Lookup API](https://fous.com/tools/icann-lookup.md): Public domain registration lookup using ICANN registration data.
- [All Developer tools tools](https://fous.com/tools/category/developer-tools)