Free tools API

The free tools on getuptimely.com have an API that needs no account and no key. Call it from a terminal, a script, a CI job or an AI agent. It is the same check the Is it down? pages run.

Every endpoint follows the same rules:

• No authentication. No key, no cookie, no login.
• CORS is open to every origin, so a browser page on any site can call it.
• JSON by default. Send Accept: text/markdown to get the answer as Markdown, which reads better in an agent's context.
• Errors are RFC 9457 problem details (application/problem+json). Branch on code, or on type, which is a link to the matching section below.
• Rate limited per address: 30 calls a minute and 300 a day. Past either, the answer is 429 with a Retry-After header.
• Every answer carries X-Tool-Docs, the address of this page.

The OpenAPI 3.1 description is at getuptimely.com/api/tools/openapi.json, and both it and the /v1 API are listed in the API catalog.

Is a site up? GET /api/tools/check

curl "https://getuptimely.com/api/tools/check?url=github.com"

curl -H "Accept: text/markdown" "https://getuptimely.com/api/tools/check?url=github.com"

url is a domain (example.com) or an http:// or https:// address. The path is ignored: the check requests the site's home page. POST with the JSON body {"url": "example.com"} does the same.

What the check does:

1. Resolves the name and refuses the request if any address is not on the public internet (private, loopback, link-local and cloud metadata ranges).
2. Requests the home page on port 443 (or 80 for http://), following up to 5 redirects. Each redirect is checked the same way; one to another port or a private address is not followed.
3. Reads the status line, the response time and, over HTTPS, the certificate. The page body is never downloaded.

The whole check takes at most 10 seconds. A result is reused for 60 seconds, for every caller, so a site is never sent more than one check a minute from this API.

The answer

{
  "tool": "is-it-down",
  "target": {
    "scheme": "https",
    "host": "github.com",
    "url": "https://github.com/"
  },
  "verdict": "up",
  "summary": "github.com is up. It answered HTTP 200 OK in 182 ms.",
  "checkedAt": "2026-10-21T18:04:11.402Z",
  "http": {
    "status": 200,
    "statusText": "OK",
    "finalUrl": "https://github.com/",
    "responseTimeMs": 182,
    "redirects": []
  },
  "failure": null,
  "certificate": {
    "validTo": "2027-02-05T23:59:59.000Z",
    "daysLeft": 107,
    "issuer": "Sectigo Limited",
    "trusted": true,
    "problem": null
  },
  "warnings": [],
  "cached": false,
  "ageSeconds": 0,
  "cacheTtlSeconds": 60,
  "vantage": "One HTTP request from Uptimely's checker, a single location. A site can be up for us and down in your region, or the reverse.",
  "links": {
    "page": "https://getuptimely.com/is-it-down/github.com",
    "monitor": "https://app.getuptimely.com/accounts/register",
    "docs": "https://getuptimely.com/docs/free-tools-api"
  }
}

verdict is down when the site did not answer (the reason is in failure.reason: dns_failed, dns_unavailable, connection_refused, connection_reset, timeout, tls_failed, connection_failed or too_many_redirects) or when it answered with a 5xx status. A 4xx answer is up with a warning: the server is running, and some sites refuse automated requests this way. A site that is down is still an HTTP 200 answer from this API — the finding is in the body.

The check runs from one location. For continuous checks from more than one, with alerts, create a monitor in Uptimely.

Errors

{
  "type": "https://getuptimely.com/docs/free-tools-api#problem-invalid_url",
  "title": "Invalid url",
  "status": 400,
  "detail": "Only the standard web ports (80 for http, 443 for https) can be checked.",
  "code": "invalid_url",
  "reason": "unsupported_port"
}