You can use passport to sign in to your application. But is there a special meaning to Single Sign?

It all depends on what kind of Single Sign On you want to use. You will have to give us more information. But as mentioned Passport can do it.

I have to develop an application in laravel 5.3. The requirement is i have a main site having user management like accounts.google.com.

After register/login to this site i can access few other services(2 other site in laravel say child sites/sub services like google drive, gmail etc )

My requirement is, i can login to main site and can access to the another 2 service sites without login. The user login will be from main site only.

How this could be done in [ Laravel 5.3]/Passport ?

@balakan, I am also wondering is it possible to use laravel passport as pure oauth/SSO server ? I mean the following:

• I have 3 different project in different codebases.
• I want to introduce SSO in fourth project/codebase

Could I achieve it using laravel passport?

This could be the special meaning of SSO - using it among different applications. And not sure if laravel passport support it.