OnlineOrNot is a 100% self-funded, independent uptime monitor, and its free Hobby plan is honestly one of the better ones in the category: 3-minute checks, and — rare among free tiers — Slack, Discord and Telegram alerts included at $0. Most rivals' free plans are email-only (StatusCake, Site24x7, UptimeRobot all gate chat/webhook alerting behind paid tiers). If your alert destination is a team chat channel and you're happy to sign up, OnlineOrNot's free plan may simply be the better tool — this page won't pretend otherwise.
The two catches, per their own feature-comparison table (September 2026): raw webhooks are Pro-only, from $15/month — on the free plan you cannot point an alert at your own HTTPS endpoint, a PagerDuty-style bridge, a CI hook, or an agent — and everything starts with an account and a dashboard. If the alert you wanted is a webhook, or you want the check armed from a terminal, script, CI step or agent in the next ten seconds with no signup form, that's the narrow moment this page is for: one curl arms an uptime check whose alert is an HMAC-signed webhook (Slack and Discord formats auto-detected too), plus a public status page, README badge and Atom feed. Small free capacity, honestly stated below.
Facts from OnlineOrNot's own pricing page, September 2026 (verify current numbers yourself). The free Hobby plan: 3 uptime monitors at 3-minute intervals, up to 2 users, email + Slack + Discord + Telegram alerts, 1,000 browser-check runs/month, 1 status page (custom logo, 100 email subscribers), 14-day data retention, and — genuinely notable — authenticated API and MCP access even on the free plan. Not on Hobby: webhooks, SMS, on-call integrations, maintenance windows, custom status-page domains. Pro (from $15/month) adds 30-second checks, 10 monitors (+$10 per 25 more), webhooks, SMS, on-call integrations, unlimited users and 12-month retention.
Two things said plainly. First: their free 3-minute interval is 10× faster than our 30-minute checks — if detection speed matters, they win that axis outright. Second: their real product is more than pinging — browser checks (synthetic monitoring, with a free monthly allowance), keyword/API monitors, multi-location verification before alerting, a real dashboard, and a proper status-page product. We have no equivalent for most of that. This page is about one narrow moment: a webhook-alerting uptime check armed in ten seconds without a signup form.
curl -X POST https://mockbird.mockbird.workers.dev/api/status/monitor \
-H 'content-type: application/json' \
-d '{"url":"https://api.example.com/health","notify":"https://your-endpoint.example.com/hook"}'We GET your URL every 30 minutes from Cloudflare's network (8s timeout, redirects followed, 2xx/3xx = up). Your URL is probed immediately, so the response doubles as a one-shot "is my site up from outside?" check — and it contains everything else you need:
{
"id": "mon-XXXX",
"secret": "…",
"current": { "ok": true, "http_status": 200, "ms": 87 },
"checked_every_minutes": 30,
"status_page": "https://mockbird.mockbird.workers.dev/status/mon-XXXX",
"badge_svg": "https://mockbird.mockbird.workers.dev/status/mon-XXXX/badge.svg",
"feed_atom": "https://mockbird.mockbird.workers.dev/status/mon-XXXX/feed.xml"
}notify takes a Slack incoming webhook, a Discord webhook, or any HTTPS endpoint — the format is sniffed from the host: hooks.slack.com gets {"text": …}, discord.com/api/webhooks gets {"content": …}, and anything else gets JSON signed with your monitor's secret (x-mockbird-signature: sha256=hex(hmac-sha256(secret, body)) — verify it like a Stripe webhook). That "anything else" is exactly what OnlineOrNot's free plan can't do: your own endpoint, a serverless function, an incident bridge, an agent's inbox. A confirmation delivery hits your webhook at create time so you know the channel works before you rely on it.
Alerting is deliberately quiet: one POST when the URL goes down, one when it recovers, debounced — two consecutive checks must agree, so a single blip never pages you. No retries, best-effort delivery, and 5 consecutive failed deliveries auto-remove the monitor (a dead webhook can't rot forever). No email, no SMS, no Telegram here, stated plainly — the webhook is the product.
Every monitor gets a public status page at an unguessable URL showing the hostname only, an SVG badge for the README, and an Atom feed of down/recovered events for anyone who'd rather poll than be POSTed at:
[](https://mockbird.mockbird.workers.dev/status/mon-XXXX)Honest scope note: OnlineOrNot's status pages are a real product — incident history, email subscribers, custom logo even on free, custom domains on Pro. Ours is a single-monitor page with current state and recent events. If you need customer-facing incident communication, theirs wins.
OnlineOrNot counts heartbeat monitors against the same monitor quota (their monitors cover "endpoints, keywords, APIs, and heartbeats"), so a cron watch spends one of the 3 free slots there. Here heartbeats are a separate free pool: POST /api/status/heartbeat returns a secret ping URL; append && curl -fsS -m 10 <ping_url> to the cron job, and if pings stop arriving within period + grace you get one service.down webhook, one service.up on resume. Full recipes: cron-job monitoring with one curl.
| OnlineOrNot concept | Here |
|---|---|
| Uptime monitor (3 free, signup first) | POST /api/status/monitor {"url": …, "notify": …} — no account, response includes the current check |
| Slack / Discord / Telegram alerts (free there — genuinely rare) | Slack + Discord auto-detected from the notify host. No Telegram here, stated plainly |
| Webhooks (Pro, from $15/mo there) | The default and only channel — HMAC-signed JSON to any HTTPS endpoint, free |
| Heartbeat monitor (counts against the monitor quota there) | POST /api/status/heartbeat — separate free pool, 30 min–7 day periods |
| Status page (1 free, subscribers + logo) | One per monitor, unguessable URL, hostname-only — plus badge + Atom feed. Theirs is the fuller product |
| 3-min free checks, 30-sec paid, multi-location verification | Honest: 30-minute checks from Cloudflare's edge as a single logical vantage point — they win this axis outright |
| Browser checks / synthetic monitoring (1,000 runs/mo free) | No equivalent. We speak HTTP GET only |
| Keyword / API assertion monitors | No equivalent. 2xx/3xx = up is our whole truth table |
| Authenticated API + MCP access (free there) | Same URLs you created with — self-documenting on bare GET — and our monitors are also MCP tools, no auth at all |
Facts checked September 2026 against each vendor's own pricing page — verify current numbers yourself:
| Free tier | Pick it when | |
|---|---|---|
| OnlineOrNot | 3 monitors, 3-min checks, email + Slack/Discord/Telegram alerts, 1 status page, 1,000 browser-check runs/mo, API + MCP; webhooks/SMS/on-call from $15/mo | Your alert destination is a chat channel, you want a dashboard and fast free checks, and signing up is fine. Self-funded indie, if that matters to you (it's a good sign). |
| UptimeRobot | 50 monitors, 5-min checks, dashboard; webhooks and heartbeats are paid (details) | You want a free dashboard watching many sites and email alerts are enough. |
| StatusCake | 3 monitors, 15-min checks, email to 1 address; integrations from $24.49/mo (details) | Email is enough and you want a dashboard without UptimeRobot's monitor sprawl. |
| Site24x7 | 1-min checks (fastest free interval around), email alerts; webhooks from ~$36/mo (details) | Email alerts are enough and detection speed is everything. |
| Mockbird | URL monitors: 3 live per IP (deleting frees the slot), 30 total, 30-min checks. Heartbeats: 5 live per IP. Webhook + Slack + Discord alerts, status page/badge/feed — free, no account | The alert must be a raw webhook, and you want it armed this minute from a terminal, CI step, script or agent. |
Where OnlineOrNot wins, plainly: 3-minute free checks (10× faster than ours), free chat-channel alerting that almost nobody else gives away, browser/synthetic checks, keyword and API monitors, multi-location verification, real dashboards and a real status-page product — and a Pro tier at $15/month that's cheap for what it adds. We do: one curl, no signup, webhook down/up alerts with HMAC signatures, public status artifacts, and free heartbeats in a separate pool — at $0 where their webhook alerting starts at $15/month.
# info + 24h ok-rate + recent checks · then stop
curl "https://mockbird.mockbird.workers.dev/api/status/monitor/mon-XXXX?secret=YOUR_SECRET"
curl -X DELETE "https://mockbird.mockbird.workers.dev/api/status/monitor/mon-XXXX?secret=YOUR_SECRET"Both endpoints self-document on a bare GET. The complete walkthrough of the monitor feature is the uptime monitor API guide; we also run a public tracker of 50+ developer APIs at /status that you can subscribe alerts to without using a monitor slot.