What is an HTTP status code?
Every time a browser or a search engine asks a server for a page, the server answers with a three-digit status code before it sends anything else. The code says what happened: the page is here, it has moved, it does not exist, or the server failed.
The first digit is the class. 2xx means success, 3xx means the page is somewhere else, 4xx means the request was wrong or the page is missing, and 5xx means the server broke. Visitors rarely see these codes, but search engines read every one of them.
Common status codes
| Code | Name | What it means | |
|---|---|---|---|
| 2xx | 200 | OK | The page exists and was sent. This is what an indexable page should answer. |
| 3xx | 301 | Moved Permanently | The page has a new address for good. Search engines move the old URL's ranking to the new one. |
| 302 | Found | A temporary redirect. The original URL stays the one that is indexed. | |
| 304 | Not Modified | The page has not changed since the copy the client already holds, so nothing is resent. | |
| 307 | Temporary Redirect | Like 302, but the request method must not change: a form post stays a post. | |
| 308 | Permanent Redirect | Like 301, but the request method must not change. | |
| 4xx | 400 | Bad Request | The server could not understand the request, often a malformed URL or header. |
| 401 | Unauthorized | The page needs a login. Search engines cannot index what they cannot sign in to. | |
| 403 | Forbidden | The server refuses to show the page, sometimes only to bots. | |
| 404 | Not Found | There is no page at this address. It drops out of search results over time. | |
| 410 | Gone | The page was removed on purpose and is not coming back. It drops out faster than a 404. | |
| 429 | Too Many Requests | The client sent too many requests and is being slowed down. Crawlers back off. | |
| 5xx | 500 | Internal Server Error | Something broke on the server. Repeated 500s make search engines crawl less. |
| 502 | Bad Gateway | A server in front of the site got a bad answer from the one behind it. | |
| 503 | Service Unavailable | The server is down or overloaded for now. The right code for planned maintenance. | |
| 504 | Gateway Timeout | A server in front of the site waited too long for the one behind it. |
Redirects and SEO
A redirect sends visitors and crawlers from one URL to another. Use a 301 or 308 when a page has moved for good, so search engines index the new address and pass it the old one's links. Use a 302 or 307 only when the move is temporary.
Keep chains short. Every extra hop costs time, and crawlers stop following a chain after a handful of hops. A chain that leads back to itself is a redirect loop: the page can never load. The checker follows up to 10 redirects and shows each one, so you can link straight to the final URL.
Noindex and nofollow
Noindex tells search engines not to show a page in their results. Nofollow tells them not to follow the links on it. A page can say either in a <meta name="robots"> tag (or <meta name="googlebot">) in its HTML, or in an X-Robots-Tag HTTP header, which also works for PDFs and images.
The checker reads the final page's tags and headers the way Google does: none means both, and when two rules disagree the stricter one wins. An unexpected noindex is one of the most common reasons a page never appears in search, so check new and redesigned pages before you wait for traffic.
Questions
What does the Status Code Checker show?
For one URL it shows the HTTP status code the server answers, every redirect it follows with each hop's URL and code, the final URL and its code, and whether the final page is set to noindex or nofollow by a robots meta tag or an X-Robots-Tag header.
Why does my URL show a 301 when the page loads fine in my browser?
Your browser follows redirects without telling you. A 301 means the address you typed is not the page's real address: the server sent the browser on to another URL, which answered 200. Link to the final URL directly so visitors and crawlers skip the extra hop.
Is a 302 redirect bad for SEO?
Not when the move really is temporary. A 302 or 307 tells search engines to keep the original URL indexed. If the page has moved for good, use a 301 or 308 so the new URL is the one that gets indexed and collects the links.
What is the difference between noindex and nofollow?
Noindex asks search engines to leave the page out of their results. Nofollow asks them not to follow the links on the page. Either can be set in a robots meta tag in the HTML or in an X-Robots-Tag HTTP header, and the checker shows which one set it.
Why couldn't my page be fully checked?
Some sites answer automated requests with a bot protection page instead of the real page. The checker reports the status code that page returned, but it cannot read the real page's robots tags, so noindex and nofollow are shown as unknown.
How many URLs can I check?
You can run 20 free checks a day, with no account. The count is per network and resets at midnight UTC. Each check follows up to 10 redirects.