How do I identify URL parameter issues?
There are a few options here but given the nature of these issues, it really can pay to commission an SEO expert to carry out an audit. The first place I’d recommend looking at is carrying out an SEO crawl, using software such as Screaming Frog, SEMrush or SiteBulb. The tool should highlight excessive URLs if parameters are rife on the site, for example, if you have a small site but the crawler has picked up, say 10k+ URLs, all with parameters. You can often filter or export the URLs – identify ones with ? or & in there.
The second method is to look into the Google Search Console > Coverage area, here you can see if Google is having a hard time processing a lot of URLs, you may see a lot of parameter URLs in Crawled or Discovered – Not Indexed. You can also do something similar with Bing Webmaster Tools. A final step could be to go into Settings > Crawl data within Search Console, this will highlight how many URLs are being crawled per day, if there are spikes completely out of the normal then it could be due to parameter handling.