Free Internet Censorship & Website Blocking Test
Compare browser and server HTTP observations to investigate why a public website may be unreachable from your connection.
Check website reachability
Compare an actual browser request with a server-side HTTP availability check for a public website.
How to use this tool
Follow these steps to get observations you can interpret and act on.
Choose a public website
Enter an HTTP or HTTPS URL that you want to investigate. Avoid sensitive or authenticated links.
Run the comparison
The browser attempts a request and the application server independently checks HTTP availability.
Investigate the difference
Read any browser-policy notes, status codes and server errors. Repeat from another trusted network if you need more evidence.
How the website censorship test works
The reachability test attempts a request from your browser and compares it with an application-server availability check. Different observations can help you narrow down a connection problem, but the comparison cannot establish the cause by itself.
Browser policy and cross-origin restrictions can hide response details. A difference between browser and server results is evidence to investigate, not proof of censorship.
Understanding your results
- A browser failure can come from CORS, mixed-content restrictions, extensions, DNS, connection errors or site policy.
- A server success only confirms reachability from that server’s route; it does not prove intentional blocking on your network.
- For independent geographic observations, use the global uptime test. This browser/server comparison does not run regional Globalping probes.
Privacy & important limitations
- The selected website receives the attempted browser request, and the application server receives the URL for its comparison.
- Do not include credentials or private tokens in the URL. Treat differences as evidence to investigate rather than a definitive censorship verdict.
Measured findings include their source and scope. An unavailable check is never counted as a pass, a threat or a score.
Frequently asked questions
Does a failed browser request prove censorship?
No. Browsers restrict access to some cross-origin responses, and ordinary network or site errors can also cause failures.
Why does a page open normally but fail this check?
Top-level navigation and a script’s cross-origin request follow different browser rules. A website can open in a tab while limiting scripted response access.