Cookie conflict on subdomains?

Question

Laravel

Hello, please tell me how to be.
There are 3 sites: site.ru, m.site.ru and dev.site.ru.
The first 2 are full and mobile versions, they use the same database. In order for a user authorized on one domain to remain authorized when going to another, I specified in the settings that cookies on these domains be set for the site.ru domain.
The problem is that dev.site.ru is a domain for testing, it uses a different base. In his settings, I indicated that cookies were set for dev.site.ru, but at the same time, on this domain, the site also sees cookies from site.ru.
As a result, each cookie becomes 2 for site.ru and dev.site.ru.
How to separate these domains correctly?

Answer 1

> How to separate these domains correctly?
options:
1. add prefixes for cookies: dev_username for example
2. transfer dev to another domain (site.com)
3. when setting cookies on dev.site.ru, delete all cookies from site.ru