Is it possible to use a backslash in a URL on Webflow? If not, should I do 301 redirects from URLs with backslashes to URLs without backslashes if the marketing agency already did redirects?

In Webflow, it is not possible to use a backslash in a URL structure. The reason for this limitation is that backslashes are reserved characters used for special purposes in URLs. Instead, Webflow uses forward slashes (/) to separate different elements of the URL.

If your marketing agency has already set up 301 redirects for URLs with backslashes to URLs without backslashes, that implies they have redirected traffic from the old URLs to the new ones. Redirects ensure that users and search engines are properly directed to the correct content, even when the URL structure has changed.

Since Webflow does not permit the use of backslashes in URLs, it is recommended to stick with forward slashes in your URL structure. By avoiding backslashes, you maintain compatibility and ensure that users can access your content without any issues.

To summarize, you should continue to use forward slashes in your URLs in Webflow. If the marketing agency has already implemented 301 redirects from URLs with backslashes to URLs without backslashes, it means they have taken care of preserving your website's SEO and user experience during the transition.