With Webflow natively, absolutely not.
1) The Common Pattern
The common pattern is to separate concerns with Webflow. Split it up between the application, and everything else.
The latter (everything else) being Webflow. Blog, website, marketing pages, lead gen, forms, amazing designs, animations & interactions, etc.
The former (the application) being something other than Webflow.
People usually split those up by domain.
Webflow site: https://example.com
That all said, the line is starting to blur.
You have Webflow’s recently announced DevLink. This will allow you to take the components you build in Webflow, bind and use them in a React app.
It’s not yet available, but looks exciting.
This is the venerable integration that get’s you as close as possible, today, without a ton of custom coding or specific domain knowledge.
This third party solution is very mature and popular with Webflowers.
Here is an advanced example of integrating Memberstack authentication with AWS services and glueing that together with Make (Integromat):
It’s easy to lean on the Webflow CMS, and move that data around with Webflow Webhooks. A popular approach is to store your data in Airtable or Google Sheets.
Wized is the more advanced, not for the weak-at-heart folks who want to use Webflow.
It’s not publicly available, invite only. I have access, it rocks, but it’s very advanced.
For what you’re asking for, your best approach is option number 1.
Use Webflow for all of the non-application work (many benefits to this), and use another solution for the application that allows you to take advantage of Railway.
Hope that helps!