TCP monitoring
Monitor ports that HTTP cannot see
Open a TCP connection to a host and port on a schedule. Perfect for databases, mail, MCP, and anything that is not a URL.
Free for now. Help us shape what comes next.
The problem
HTTP-only tools leave your Postgres, Redis, SMTP, and custom TCP services blind. When the port stops accepting connections, you learn from a cascading app failure instead of an alert.
How we solve it
Add hostname + port, pick an interval, and we attempt a TCP connect. Up means the port accepted the connection. Down means it did not. You get an email when it matters.
Technical capabilities
How TCP Checks works in CalmCanary.
Configuration & setup
Enter hostname (or IP) and port. No packet crafting, no agent on the box: just connectivity from our checker to your public endpoint.
db.example.com:5432 - mcp.example.com:8080
Alerting
Failed connects flip the monitor down and trigger email alerts. Same loop as HTTP: check, status, notify.
Email on down - shared dashboard with HTTP monitors
Performance & reliability
1-minute or 5-minute intervals with recorded timing so you see connect latency, not just binary up/down.
Intervals: 1m - 5m - connect time tracked
What TCP is good for
Databases, mail ports, game/MCP servers, and internal services exposed via tunnel or public IP, wherever a successful socket open is the health signal.
Postgres - Redis - SMTP - custom TCP
How it works
Three steps. No agents. No ceremony.
Create a TCP monitor
Choose TCP, enter hostname/IP and port, set 1-minute or 5-minute checks.
We open the socket
On each interval we attempt a TCP connection and record success or failure with timing.
Alert when the port dies
If connects fail, you get an email. Restore the service and the monitor returns to up.
Who this is built for
Agencies
Keep an eye on client databases and mail ports alongside their websites in one CalmCanary account.
Indie / AI builders
Watch MCP servers, Redis, and Postgres without standing up a separate infra monitor.
Ops-light teams
Zero-maintenance port pings when you do not need full APM and only need to know if the port accepts connections.
Paying for a suite just to watch a few TCP ports?
See CalmCanary vs Better StackFAQs
How is TCP different from HTTP checks?
HTTP requests a URL and evaluates the response. TCP only opens a connection to host:port. Ideal when there is no HTTP surface.
Can I monitor databases?
Yes, if the port is reachable from the internet (or via a public tunnel). We verify connectivity, not query correctness.
What intervals are available?
1 minute or 5 minutes. Same as HTTP monitors.
Is TCP monitoring free?
Yes on the launch tier, with email alerts included.
More features
Start using TCP Checks free
Launch tier monitoring with a direct line to the team. Early LTD seats for early users.