TCP port monitoring
Not everything speaks HTTP. PingDog opens a TCP connection to a host and port on your schedule and measures how long it takes — so a database, broker or mail server that stops accepting connections pages you.
What PingDog checks
- TCP connection succeeds to the given host and port
- Connect time is measured on every check
- Alerts when the port stops accepting connections
Databases, message queues, SMTP servers, Redis, game servers, SSH — the services that keep an app alive often expose a raw port, not a web endpoint. A TCP check confirms the thing is actually accepting connections, which is frequently the earliest sign of trouble (a connection pool exhausted, a process crashed, a firewall change).
Point PingDog at tcp://host:port and it does the rest, on whatever schedule you build.
Anonymous, pay-per-check
Like everything on PingDog, this check needs no account: your key is the account, you pay once at $0.0005 per delivered check in USDC on Base, and nothing renews. A real free tier runs up to 3 monitors at a 5 minutes interval with no payment at all. See how pricing works.
Frequently asked
How do I specify a TCP target?
Give the target as tcp://host:port. PingDog opens a connection to that host and port and measures the connect time on each check.
Can I monitor a database or mail server?
Yes — anything that listens on a TCP port, including databases, message brokers and SMTP servers, as long as you are authorized to monitor it.