I'm building a fantasy football app and am unsure whether to use one domain for everything or put the application on something like app.example.com while keeping the marketing site at example.com.
I've seen advice recommending a separate app subdomain for easier security boundaries, independent deployments, and the possibility of letting a marketing team manage the public site separately. On the other hand, companies such as Sleeper, Airtable, Figma, Canva, Trello, Dropbox, and GitHub commonly make the main domain serve as the public site and app entry point, with the experience changing after login.
I'm leaning toward using the main domain, but I want to avoid creating unnecessary migration, authentication, cookie, routing, SEO, or maintenance problems later. Are there strong technical reasons to choose a subdomain from the beginning, or is this mostly an organizational and architectural preference?
4 Answers
For SEO, the important content should generally remain on the main domain. If the app is mostly behind a login, its pages probably aren’t contributing much to search traffic anyway. The decision should therefore be based on operational needs: separate deployments, different hosting, team ownership, isolation, or a need to keep the public site static and highly available.
You don’t need a subdomain unless you have a concrete reason for one. Early on, putting the marketing pages and app under the same domain is usually simpler for routing, authentication, cookies, and the overall user experience. You can always split things later if the product grows or the teams and codebases need to become independent.
Don’t choose based on generic SEO folklore or claims that one structure is universally correct. Pick the arrangement that keeps your authentication and routing simplest. If users are expected to visit the main domain, sign in, and immediately use the product, keeping everything together is perfectly reasonable. If you already know the marketing site and application will be managed or deployed independently, a subdomain is a useful boundary.
So the practical answer is to use the main domain for now and introduce a subdomain only when there’s an actual organizational or technical requirement?
A common setup is to keep the marketing site at the main domain and use a subdomain for the app, but the main benefit is separation rather than SEO. The marketing site can be hosted and deployed independently, possibly by a different team or provider, while the app can have its own release cycle and security boundaries. It also means the marketing site can remain available if the app is down. That said, these benefits matter more once the product, team, or infrastructure becomes larger.
That makes sense. I was mostly worried that choosing one domain now would create a painful migration later, but I don’t currently have a technical need for a separate app host.