Ask HN: How do you manage “static” pages on your micro SaaS website?

I wonder how small scale SaaS developers manage their static content on the same domain as a Web app.

I mean all those landing pages, legal, promo materials etc.

Yes, you can point domain.com -> netlify, while app.domain.com -> your frontend server.

But what if you need a bit more than that? Like use auth cookies, expose some web-app features, urls on root domain etc.

How do you combine all that with the rest of static pages' you want to keep updating at runtime without managing own CMS?

Any tools, libs, best practices?