Httprobe
Probe a list of hostnames (max 16) for HyperText Transfer Protocol (HTTP) and HyperText Transfer Protocol Secure (HTTPS) availability. One per line or comma-separated.
Monitor this automatically
NetTests can run this check on a schedule, preserve historical results, compare changes over time, and alert you the moment something breaks.
Start monitoring free → See all monitoring productsFrequently Asked Questions
What does the HTTP Availability Check test?
It probes each hostname for both HyperText Transfer Protocol (HTTP) (port 80) and HyperText Transfer Protocol Secure (HTTPS) (port 443) availability, reporting the HTTP status code and response time for each. Submit a list of domains to quickly identify which are reachable and whether they redirect HTTP to HTTPS. Useful for bulk uptime checks across multiple subdomains or a list of monitored sites.
How is this different from a ping?
Ping tests Internet Control Message Protocol (ICMP) reachability at the network layer — a server can be 'pingable' but have its web server down, or block ICMP while serving HyperText Transfer Protocol (HTTP) normally. This tool makes actual HTTP GET requests, confirming the web service itself is responding and capturing the status code (200, 301, 403, 503, etc.).
What do different HTTP status codes mean?
200 — OK, content returned. 301/302 — redirect (common for HyperText Transfer Protocol (HTTP)→HyperText Transfer Protocol Secure (HTTPS)). 401/403 — authentication required / forbidden (server is up but content is protected). 404 — path not found but server is reachable. 503 — service unavailable (server is up but overloaded or in maintenance). A connection error means the server is unreachable entirely.
What is the maximum number of hosts I can check?
Up to the configured limit per request. Enter one hostname per line — subdomains, domains, or Internet Protocol (IP) addresses. The tool probes all hosts in parallel to keep scan times low. For ongoing monitoring of many sites, use our Dashboard monitoring feature.