Not every job can make an HTTP call. Locked-down networks, legacy cron boxes, and internal servers often can only send mail through an SMTP relay. Every Seiri monitor gets a unique @ping.seiri.app address — send it an email when your job finishes, and Seiri treats it exactly like a ping.
If outbound HTTPS is blocked by policy but SMTP relay is allowed, an email heartbeat gets around the restriction without a firewall exception.
Older systems that ship with `sendmail` or `mail` but no modern HTTP client can still check in without new tooling.
Some backup tools, NAS devices, and monitoring appliances only support email notifications — forward theirs to your heartbeat address.
Sometimes the fastest integration is a one-line `mail` command instead of installing curl or a client library.
Create a monitor and switch it to email mode. You'll get a unique address like a1b2c3d4@ping.seiri.app.
Any email to that address counts — subject and body don't need a special format.
Miss the expected window and grace period, and Seiri alerts you through Slack, SMS, another email, or a webhook.
Can make HTTP calls instead? See cron job monitoring for the curl-based approach.
An email heartbeat is a check-in sent by email instead of an HTTP request. Every Seiri monitor can be configured with a unique @ping.seiri.app address; when your job sends an email to that address, Seiri treats it exactly like a successful ping.
Many internal servers, legacy systems, and locked-down networks can send outbound email via SMTP relay but cannot make arbitrary outbound HTTPS calls. Email heartbeats let those systems check in without any new firewall rules or client libraries.
No. Seiri only needs to receive an email at the monitor's unique address within the expected schedule and grace period — subject and body content are not required to match a format.
The Free plan includes 1 email heartbeat, Growth includes 5, and Scale includes 25.