Why Do Some Pages Have the nab Parameter in Their URLs When There Aren’t Any Tests Running?

Nelio A/B Testing may add the nab query parameter to URLs when running tests. This parameter helps Nelio determine which variant should be loaded for a visitor.

If you still see the nab parameter in some URLs after stopping all your tests—or even after deactivating Nelio A/B Testing—your website may be serving cached versions of pages or links that were generated while a test was running.

This can happen when your site uses a caching plugin, server-side cache, or CDN.

To fix it, purge or clear all caching layers used by your website, including:

• Your WordPress caching plugin, if any.
• Your hosting or server-side cache.
• Your CDN cache.

After clearing the caches, reload the affected pages and check whether the nab parameter still appears.

If it does, see Why Do A/B Testing Parameters Appear in My URLs, and How Can I Hide Them? for more information about the parameters used by Nelio A/B Testing.