Port Checker
Test whether a TCP port is open and reachable on a public host: from the outside, the way the rest of the internet sees it. Checked from Uptimeify's EU servers.
What watches these brands watches your clients too
This check works inside your AI agent, too.
You are running by hand what Claude, Cursor or ChatGPT could do for you directly. Uptimeify offers this and 19 more checks as an MCP server: SSL, DNS, email authentication and more, right in your workflow. No account, no API key, on EU infrastructure.
Frequently asked questions about Port Checker
Open means a service accepted the TCP connection on that port: something is listening. Closed means the host answered but refused the connection, so nothing is listening on that port. Filtered means there was no answer at all within the timeout, which usually points to a firewall silently dropping the traffic, or a host that is down. The check is made from our servers, so it reflects what an outside client on the public internet sees.
No, and that is by design. The checker refuses to connect to private, loopback or reserved address ranges (such as 10.x, 192.168.x or 127.0.0.1), and it pins the connection to the resolved public IP so a hostname can't be used to reach internal systems. It also checks a single port per request rather than scanning ranges. This keeps the tool safe to offer publicly.
The connection is made from Uptimeify's EU servers, not your browser, the host and port you enter are used only to perform the check and are not stored. As an EU-built, EU-hosted provider, Uptimeify keeps this off US infrastructure and clear of US Cloud Act exposure, which matters for agencies handling client data under GDPR.
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Ready to Keep Those Ports Under Watch?
A port that's open now can be closed after the next firewall update. Uptimeify probes TCP ports on an interval and reports the failure before the service behind it turns into a ticket.