Netlify CMS is a single-page app, so the delay you're seeing is the wait for an external API to respond that the entry has saved succesfully - you wouldn't want

Netlify CMS is a single-page app, so the delay you're seeing is the wait for an external API to respond that the entry has saved succesfully - you wouldn't want to leave the page only to find out that your changes weren't saved. When using the in-memory backend (which doesn't persist changes), saving happens with no such delay. Since the delay is almost entirely from the network and external API, it shouldn't get worse with lots of files unless the external API takes longer to respond. Our current primary backend is the GitHub API, which handles lots of files without much change in response time in my experience.