Can I use API: Check browser support
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.
Unofficial. Not affiliated with or endorsed by Can I use.
Inputs
Values from the run on Oct 31, 2026, shown under Output.
- Feature, required
feature Name of the web feature to check, for example CSS grid.
CSS grid
Input as JSON
{ "feature": "CSS grid"}Output
{ "link": "https://caniuse.com/css-grid" , "browsers": [ { "notes": "See also support for subgrids At first full support: There are some bugs with overflow (1356820, 1348857, 1350925)", "browser": "Chrome", "current_support": "supported", "first_fully_supported_version": "57" }, { "notes": "See also support for subgrids", "browser": "Edge", "current_support": "supported", "first_fully_supported_version": "16" }, { "notes": "See also support for subgrids At first full support: There are some bugs with overflow (1356820, 1348857, 1350925)", "browser": "Firefox", "current_support": "supported", "first_fully_supported_version": "52" } ], "description": "Method of using a grid concept to lay out content, providing a mechanism for authors to divide available space for layout into columns and rows using a set of predictable sizing behaviors. Includes support for all grid-* properties and the fr unit.", "feature_key": "css-grid", "feature_title": "CSS Grid Layout (level 1)", "global_full_support_percent": 96.65, "global_full_and_partial_support_percent": 96.89}Code
curl https://api.fous.com/v1/runs \ -H "Authorization: Bearer $FOUS_API_KEY" \ -H "Content-Type: application/json" \ -d '{"method":"caniuse.com/check_browser_support","input":{"feature":"CSS grid"}}' # Save as fous.py, then run: python3 fous.pyimport json, os, timefrom urllib.error import HTTPErrorfrom urllib.request import Request, urlopenAPI = "https://api.fous.com/v1/runs" KEY = os.environ["FOUS_API_KEY"]HEADERS = { "Authorization": f"Bearer {KEY}", "Content-Type": "application/json" ,}def call(url, body=None): data = json.dumps(body).encode() if body else None request = Request(url, data, HEADERS) try: with urlopen(request, timeout=120) as r: return r.status, json.load(r) except HTTPError as error: message = json.load(error)["error"]["message"] raise RuntimeError(message) from errorstatus, run = call(API, { "method": "caniuse.com/check_browser_support" , "input": { "feature": "CSS grid" }})# 202: still going after 30 s. Ask again until it ends.while status == 202: time.sleep(2) status, run = call(f"{API}/{run['id']}")print(json.dumps(run["data"], indent=2))// Save as fous.mjs, then run: node fous.mjsconst api = "https://api.fous.com/v1/runs" ;const headers = { Authorization: `Bearer ${process.env.FOUS_API_KEY}`, "Content-Type": "application/json" ,};let response = await fetch(api, { method: "POST", headers, body: JSON.stringify({ "method": "caniuse.com/check_browser_support" , "input": { "feature": "CSS grid" } }), signal: AbortSignal.timeout(120_000),});let run = await response.json();// 202: still going after 30 s. Ask again until it ends.while (response.status === 202) { await new Promise((done) => setTimeout(done, 2_000)); response = await fetch(`${api}/${run.id}`, { headers }); run = await response.json();}if (!response.ok) throw new Error(run.error.message);console.log(run.data);# Connect your agent to Fous once, over MCP (Streamable HTTP):# https://api.fous.com/mcp# Set FOUS_API_KEY first: create a key at https://app.fous.com/keys.# Claude Codeclaude mcp add \ --scope user \ --transport http fous https://api.fous.com/mcp \ --header "Authorization: Bearer ${FOUS_API_KEY:?Set FOUS_API_KEY to your Fous API key}"# Codexcodex mcp add fous \ --url https://api.fous.com/mcp \ --bearer-token-env-var FOUS_API_KEY# Cursor, VS Code, Windsurf, Cline and morenpx -y add-mcp https://api.fous.com/mcp -g -n fous \ --header "Authorization: Bearer ${FOUS_API_KEY:?Set FOUS_API_KEY to your Fous API key}"# Then ask your agent:# "Use Fous to run caniuse.com/check_browser_support# with {"feature":"CSS grid"}"Over HTTP, the answer’s data holds the output. A run still going after 30 seconds answers 202 with its id: ask GET /v1/runs/{id} until it ends.
Schema
Input schema
{ "type": "object", "required": [ "feature" ], "properties": { "feature": { "type": "string", "description": "Name of the web feature to check, for example CSS grid." } }}Output schema
{ "type": "object", "required": [ "feature_title", "description", "global_full_support_percent", "global_full_and_partial_support_percent", "link", "browsers", "feature_key" ], "properties": { "link": { "type": "string" }, "browsers": { "type": "array", "items": { "type": "object", "required": [ "browser", "first_fully_supported_version", "current_support", "notes" ], "properties": { "notes": { "type": [ "string", "null" ] }, "browser": { "type": "string" }, "current_support": { "enum": [ "supported", "partial", "not supported" ], "type": "string" }, "first_fully_supported_version": { "type": [ "string", "null" ] } }, "additionalProperties": false } }, "description": { "type": "string" }, "feature_key": { "type": "string", "x-fous-developer": true }, "feature_title": { "type": "string" }, "global_full_support_percent": { "type": "number" }, "global_full_and_partial_support_percent": { "type": "number" } }, "additionalProperties": false}- Price
- 1 credit per completed run (1¢ with pay as you go); failed runs are free.
- Method
caniuse.com/check_browser_support- Returns
- feature title, description, global support percentages, link, per-browser first full support version, current support and notes
Use it from your agent
Give your agent this line. It reads SKILL.md, gets a Fous API key and connects the Fous MCP server. Its run then takes the method caniuse.com/check_browser_support with the inputs above.
Ask your agent
- Is CSS container queries safe to use in production yet? What's the global support percentage?
- Which Safari version first fully supported the :has() selector, according to caniuse?
- Check browser support for WebGPU across Chrome, Firefox, Safari and mobile browsers
- Does Firefox support the View Transitions API in its current version? Include any notes.
- Look up subgrid on caniuse.com and tell me the first version with full support in each major browser
See more
Tests a web page with Google PageSpeed Insights on mobile or desktop: performance, accessibility, best practices and SEO scores, lab timings, real-user Core Web Vitals when available, and the top suggested fixes.
pagespeed.web.dev/check_page_speedFinds Chrome Web Store extensions by keywords in store order, with each listing's developer, users, rating, rating count, short description and store link. Some listings omit developer, users or ratings.
chromewebstore.google.com/search_extensionsLooks up a Chrome Web Store extension by name or store link and returns its public listing: developer, users, rating, version, update date, size, category, description, declared privacy practices, website and store link. Permissions are null when the listing does not show them.
chromewebstore.google.com/get_extensionSearches the npm registry for JavaScript packages by description or keywords, in npm's search order, and returns each package's latest version, weekly downloads and publish date.
npmjs.com/search_packagesGets the technologies shown in a website's free BuiltWith profile, grouped in the order BuiltWith displays them. A company name is matched to its official website through a public web search.
builtwith.com/get_website_technologiesChecks in-store pickup availability for an exact Apple product configuration (name or part number) near a ZIP, postal code or city, listing nearby Apple Stores by distance with their pickup messages. No reservation is made.
apple.com/check_store_pickupReturns release and support dates for a software product, operating system or device. Windows 10 and Windows 11 return only their matching releases.
endoflife.date/get_support_datesFinds recorded data breaches whose title or website domain matches a company or website name, newest first.
haveibeenpwned.com/search_breaches