200 code masking URL redirect not masking?

site is https://libralarts.netlify.app

redirect rule is as such:
/product/:id /product.html?id=:id 200

I don’t want to update the URL bar (I want to mask the URL, aka maintain the /product/:id format) so I made the status 200, which seems like what I need according to this Netlify doc. However, the URL is changing to the one on the right (/product.html?id=:id)

@bythebootstrap If you try to load the following URL directly:

https://libralarts.netlify.app/product/thought-brigade-greeting-cards

You will see that it’s performing a 301 redirect:

So it won’t be getting caused by that rule.

Are there other redirect rules that you have in place?

It may also be worth noting that the URL’s in your HTML are all in the query string parameter format:

Which wouldn’t be handled by the proxy that you’ve mentioned.