Looks nice so far, but:
I've just noticed, your https://api.daspoll.com/api/get-user-by-email/ endpoint is not secured, probably other too.
Also I would stick to camelCase in your api, it makes things more intuitive.
You should use client and server side validation, you can easily bypass the required attribute on the survey name.
Creating accounts without verifying the email is really bad.
