The mirror of the heartbeat:
one switch that stops every loop.

Heartbeats tell you when a job died. A gate tells the job whether it should run at all. Prepend one line to any cron entry, systemd timer or agent loop — it checks its gate before every run. Halt the gate and every box on every machine stops at its next boundary. No account, no agent to install, nothing runs on your side but curl.

Arm a free gate See live gate states ↗ the fleet running this site checks its own gates

Arm a gate. One form or one curl. You get a gate URL that answers 200 RUN or 503 HALT with a JSON reason. The key is shown once — it is both the gate's address and its remote control.
Make your loops check it. One line before the work:
```
[ "$(curl -s -o /dev/null -w '%{http_code}' --max-time 5 \
  https://golemreach.com/heartbeat/gate/<key>)" = 200 ] || exit 0
```
Cron, systemd ExecStartPre=, CI step, agent-loop tick — same line everywhere.
Halt everything from anywhere. One curl (or the button below) flips the gate with a reason. Loops stop at their next boundary and see WHY:
```
{
  "state": "halt",
  "reason": "deploying v2, back by 14:00Z"
}
```
Run it back. Flip to RUN when you land. Recovery is just another flip — and if you armed Nostr delivery, every flip lands as an encrypted DM in your client.

Halt at the boundary, not mid-flight A gate is honest about what it is: jobs stop at their next check, never mid-execution. That is the safe primitive — no sidecars, no kernel modules, works on any box that can curl.

You choose the failure mode The line above is fail-closed: unreachable control plane means skip this round (safe for destructive jobs). Want fail-open instead?

[ "$(curl -s -o /dev/null -w '%{http_code}' URL)" = 503 ] &&
exit 0

— only an explicit HALT stops you.

Flips reach you Arm a notify npub and every HALT/RUN arrives as an encrypted NIP-17 DM from our alert key — plus a line in the public event feed. Nobody else in the dead-man cohort ships control-pull at all.

Agent-native Create, check and flip gates over plain HTTP/JSON — exactly how an autonomous fleet does it. This site's own babysitter refuses to resurrect the server while its gate says HALT.

Create one from a terminal right now

curl -s https://golemreach.com/heartbeat/api/gates/self-serve -H 'Content-Type: application/json' \
  -d '{"name":"nightly-fleet"}'

Response carries the gate URL, the exact shell prepend, and the flip command. Free while in beta; $5 Pro passes lift limits.

Arm a free gate

No account. The gate key is shown once, right after you submit — it is the check URL AND the flip credential.

Recipes

Cron entry (skip the run entirely):

[ "$(curl -s -o /dev/null -w '%{http_code}' --max-time 5 GATE_URL)" = 200 ] || exit 0
0 3 * * * /usr/local/bin/nightly-backup

systemd service (block the start):

[Service]
ExecStartPre=/bin/sh -c '[ "$(curl -s -o /dev/null -w '%{http_code}' --max-time 5 GATE_URL)" = 200 ] || exit 1'
ExecStart=/usr/local/bin/agent-loop

Agent loop (check every tick, Python):

import os, urllib.request
if urllib.request.urlopen(GATE_URL, timeout=5).status != 200:
    raise SystemExit("gate says halt")

Flip remotely:

curl -s https://golemreach.com/heartbeat/api/gates/flip -H 'Content-Type: application/json' \
  -d '{"key":"<key>","action":"halt","reason":"deploying"}'

The mirror of the heartbeat:one switch that stops every loop.

Create one from a terminal right now

Arm a free gate

Recipes

The mirror of the heartbeat:
one switch that stops every loop.