A crawl of your website will find all pages that are redirected, as well as the pages they are redirected to. Pages that are redirected return a status code of 3xx, which makes them easy to find in the the crawl results.
Here's how to identify any redirection loops on your website using Oncrawl.
Find redirect loops
Information on redirected pages can be found in the crawl analysis results. Because redirected pages are identified based on their status code (302 or 301), you'll find this information under Indexability > Status codes.
The Redirects, chains and loops chart will show you all of the pages that are part of a redirect loop.
Click on the number to go to a list of these pages in the Data Explorer.
From here, you can explorer or export this information.
How to read the Redirects, chains and loops table
Here is the type of information you can find in this table:
Pages with single 3xx redirect to final target: 5 779 pages are redirected to a page that doesn't get redirected elsewhere.
Pages in crawl that are 3xx final targets: 5 175 pages (that aren't redirected themselves) have redirected URLs pointing to them.
There are a lot of links (444 101 + 994 322) links that point to redirected pages, which should instead point to one of the 5 175 pages at the end of a chain.
Among the links are correctly set up on your site 1 973 765 of them point to a page that is the target of a redirect. (This information isn't very actionable, but it might be reassuring!)
If you have follow inlinks to pages in this table, you'll probably want to correct them:
First priority: lines 3 and 4 (site exploration is broken for users)
Second priority: line 2 (prevent redirect chains)
Third priority: line 1 (prevent redirects in your site structure)
Find redirect loops and chains using URL Details
You can also click on the URL in the Data Explorer to show the URL details for any page in a redirect loop. Scroll down to the 3xx redirection chain section to view a graphical representation of the loop--and of any chains leading into it:
The example above shows a chain of redirects leading to a loop created when a page is redirected to itself.