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Dead Man's Snitch alternative — a free dead man's switch with one curl, no account

Dead Man's Snitch more or less named this category. Since 2012 the pitch has been exactly right: a scheduled job's worst failure is silence — the backup that nobody is even trying to run anymore — so instead of a monitor calling your job, your job checks in with a "snitch" URL, and when the check-ins stop, the alarm fires. Simple, correct, and it's been quietly saving nightly backups for well over a decade.

1. First, honestly: the snitch model works

If you already pay for Dead Man's Snitch, there's little reason to move. The tool is mature, the model is right, and their Field Agent CLI does something we don't: it wraps your command, so a check-in can carry the job's exit status and captured output — when a job starts failing, you see why in the alert, not just that it went quiet. Higher plans add smart alerts and error notices on top.

What this page is for is the pricing wall in front of all that (from their own plans page, September 2026):

• The free plan is one snitch — "1 single solitary Snitch", in their words — and it still requires an account signup first.
• The $5/mo Little Birdy plan gets you 3 snitches with basic intervals.
• Integrations (Slack and friends) appear on the $19/mo Private Eye plan; below that, alerts are email.
• Smart alerts and error notices are on the $49/mo plan.

For a company cron fleet, fine — $19/mo is cheap insurance. But "I have one script and I want the switch armed right now, alerting my Slack, without creating an account" is not a plan they sell. It's the whole product here, free.

2. The one curl

curl -X POST https://mockbird.mockbird.workers.dev/api/status/heartbeat \
  -H 'content-type: application/json' \
  -d '{"name":"nightly backup","period_minutes":1440,"notify":"https://hooks.slack.com/services/T000/B000/XXXX"}'

period_minutes is how often the job is supposed to run; notify is a Slack incoming webhook, a Discord webhook, or any HTTPS endpoint you control. The response arrives with everything you need — a secret ping_url your job will curl, a management secret, and a public status page + badge + Atom feed. A confirmation delivery hits your webhook immediately so you know the channel works, and creation counts as the first check-in: the clock is already running.

No webhook handy? Omit notify and you get a pollable heartbeat instead: the create response includes a poll URL that returns any missed-check-in / checked-in-again transitions since your last poll plus the current ping age — no endpoint to host. How poll mode works.

3. Snitch → Mockbird translation

4. Wire it into the job

# crontab: run backup at 03:00, check in only on success
0 3 * * * /usr/local/bin/backup.sh && curl -fsS -m 10 https://mockbird.mockbird.workers.dev/ping/p-XXXX

The && means a crashing job doesn't check in — so one line covers the job failing, the job never starting, and the machine being gone entirely. The same line works in a systemd timer's ExecStartPost, a GitHub Actions scheduled workflow's last step, or at the end of an agent's recurring task. When the pings stop arriving within period_minutes + grace (default: half the period, clamped 5m–24h), your webhook gets one service.down event; when they resume, one service.up. No nagging. Formats are sniffed from the URL — hooks.slack.com gets {"text": …}, Discord gets {"content": …}, anything else gets JSON signed with your secret (x-mockbird-signature, verification snippet here).

5. The status page and badge (something a snitch doesn't have)

Every heartbeat gets a public, unguessable-URL status page (/status/hb-…), a live README badge (/status/hb-…/badge.svg), and an Atom feed of missed/resumed events. The ping URL is a separate secret from the page URL — embed the badge in a public README and nobody who sees it can fake a check-in. Dead Man's Snitch keeps snitch state inside the dashboard; here "is the nightly backup alive?" is a link you can hand to anyone.

6. Honest comparison

Facts checked September 2026 against each vendor's own pricing pages — verify current numbers yourself:

Where Dead Man's Snitch wins, plainly: Field Agent's output/exit-status capture (an alert that says what broke beats an alert that says "went quiet"), email alerts without any webhook setup, smart alerts and error notices on higher plans, first-class Heroku Scheduler support, a browsable per-snitch history, and fourteen years of production trust. We do: one curl, no account, webhooks free from the first dollar you don't spend, a public status page + badge + feed, and periods anywhere from 30 minutes to 7 days rather than fixed interval tiers.

7. Managing it

# info + ping URL + recent evaluations
curl "https://mockbird.mockbird.workers.dev/api/status/heartbeat/hb-XXXX?secret=YOUR_SECRET"

# disarm
curl -X DELETE "https://mockbird.mockbird.workers.dev/api/status/heartbeat/hb-XXXX?secret=YOUR_SECRET"

The endpoint is self-documenting — GET /api/status/heartbeat returns full usage as JSON. If what you want to watch is a URL rather than a job, the same alert machinery does classic uptime monitoring: see the uptime-monitoring guide.