Know when your devices go quiet.
Your ESP32, Raspberry Pi or remote sensor sends a tiny heartbeat. If it stops, or starts reporting nonsense, LastSeen tells you. Free offline alerts for any device, on any channel, without false alarms.
Status you can trust
"Online" means we heard from it recently. You always see when, and why its status changed.
Free alerts, any channel
Email, webhooks, Discord, ntfy and more. Offline alerts are never behind a paywall.
No false alarms
Grace periods, missed-heartbeat confirmation and flapping detection. Snooze while you reflash.
Nothing to lock you in
One HTTP request is the whole protocol. Commercial use allowed. Export your data any time.
One line to start
# from a shell script, cron job or anything that can make an HTTP request
curl http://ping.lastseen.io/<device-key>
// or from an ESP32 / ESP8266
#include <LastSeen.h>
LastSeen hb("DEVICE_KEY");
void loop() {
hb.ping(readTemp());
delay(60000);
}
Email we send
LastSeen only emails people who have signed up and chosen to be notified: sign-in codes, and the device alerts you configure (a device went down or recovered). No marketing mail. Every alert email says which device it is about and links to turn that alert off. Bounces and complaints automatically stop delivery to that address.