How does the URL checker work?

Zurl’s server requests the URL the way a browser would, follows any redirects one hop at a time, and reports what happened: the status code, how long the server took to respond, where the redirects led, whether a secure (TLS) connection was made, and the content type of the final response.

Why does a site work in my browser but fail here?

Some sites block requests from data centres or from anything that is not a full browser, and some return a 403 Forbidden or a challenge page to automated clients. Others are only reachable from inside a company network or from certain countries. The checker reports what it saw from the public internet, which is not always what you see.

Does "Reachable" mean the site is safe?

No. It only means the server responded. Phishing and malware pages respond with 200 OK too. To look a URL up in threat-intelligence databases, use the URL Safety Checker.

What is the difference between a timeout, a DNS failure and a TLS failure?

A DNS failure means the domain name could not be turned into an IP address — it may not exist or may have expired. A timeout means a server was found but did not answer in time. A TLS failure means the secure connection could not be set up, usually because of an expired, self-signed or mismatched certificate.

Can I check a URL on my local network?

No. Requests to localhost, private IP ranges (10.x, 172.16–31.x, 192.168.x), link-local addresses and cloud metadata endpoints are blocked — including domains that resolve to those addresses. Otherwise the tool could be used to probe internal systems.

Are the URLs I check stored?

Results are cached for a few minutes, keyed by a hash of the URL, so repeated checks are fast. URLs are not written to logs and there is no history tied to you. See the privacy page for details.

URL ManagementFree · no sign-up

URL Checker

Find out whether a link actually works. Paste a URL to see its HTTP status, response time, redirects, TLS and content type — with a clear explanation when something is wrong.

Zurl’s server makes the request for you. URLs are not logged; results are cached briefly.

How to use the URL Checker

Step 1: Paste the URL you want to test.
Step 2: Select Check URL.
Step 3: Read the result: status code, response time, redirects, TLS and content type.

What the URL checker tells you

A link can fail in several quite different ways, and the fix depends on which one it is. The checker separates them instead of reporting a vague “down”:

Reachable — the server answered with a success code, directly or after redirects.
Client error (4xx) — the server is up but refused or could not find the page. A 404 usually means a broken link; a 403 often means bots are blocked.
Server error (5xx) — the server is up but broken or overloaded.
Timeout, DNS or TLS failure — no usable HTTP response at all.
Blocked — the URL points to a private or reserved address, so Zurl refused to request it.

When to use it

Before publishing a link in an email campaign or printing it on a flyer. When a customer says a page is broken and you want an outside view. When migrating a site and checking that old URLs still land somewhere sensible. For a code-only answer, the URL status checker is simpler; to see every hop in detail, use the redirect checker.

How the check is made

Zurl sends a single GET request per hop with a clearly identified user agent, follows up to ten redirects, and gives up after a few seconds per hop. The response body is not read or stored. Every hop is checked against the same private-network rules, so a public URL cannot redirect the checker into an internal system.

Frequently asked questions

How does the URL checker work?: Zurl’s server requests the URL the way a browser would, follows any redirects one hop at a time, and reports what happened: the status code, how long the server took to respond, where the redirects led, whether a secure (TLS) connection was made, and the content type of the final response.
Why does a site work in my browser but fail here?: Some sites block requests from data centres or from anything that is not a full browser, and some return a 403 Forbidden or a challenge page to automated clients. Others are only reachable from inside a company network or from certain countries. The checker reports what it saw from the public internet, which is not always what you see.
Does "Reachable" mean the site is safe?: No. It only means the server responded. Phishing and malware pages respond with 200 OK too. To look a URL up in threat-intelligence databases, use the URL Safety Checker.
What is the difference between a timeout, a DNS failure and a TLS failure?: A DNS failure means the domain name could not be turned into an IP address — it may not exist or may have expired. A timeout means a server was found but did not answer in time. A TLS failure means the secure connection could not be set up, usually because of an expired, self-signed or mismatched certificate.
Can I check a URL on my local network?: No. Requests to localhost, private IP ranges (10.x, 172.16–31.x, 192.168.x), link-local addresses and cloud metadata endpoints are blocked — including domains that resolve to those addresses. Otherwise the tool could be used to probe internal systems.
Are the URLs I check stored?: Results are cached for a few minutes, keyed by a hash of the URL, so repeated checks are fast. URLs are not written to logs and there is no history tied to you. See the privacy page for details.