Choose a check type

Type	Use it to detect	Health signal
Ping / heartbeat	A scheduled job stops completing, or a reported value crosses a threshold	Your sender checks in
Website	An HTTP endpoint fails or returns the wrong status code	Pingstack performs a GET
DNS	Public DNS records disappear or differ from expectations	Answers from three public resolvers
TCP	A public service no longer accepts TCP connections	A connection to a hostname and port
Domain	A registration approaches expiration	An expiration date from a domain lookup
SSL certificate	A presented certificate approaches expiration	Certificate expiration over TLS

A TCP success does not prove an application query works. A website success does not prove a background job ran. Use several checks when a service has independent failure modes.

Give checks names that identify both the service and the signal. Check kind cannot be changed after creation; create a replacement check when changing the monitoring method.

Website, DNS and TCP intervals are constrained by your plan. Domain and certificate lookups run hourly. Heartbeats follow the sender’s expected interval or cron schedule. Compare scheduling behavior.