SuperTokens is an open source authentication solution offering features like: Different types of login: Email / password, Passwordless (OTP or Magic link based).

SuperTokens.com

errr := supertokens.Init(supertokens.TypeInput{
        Supertokens: &supertokens.ConnectionInfo{
            // These are the connection details of the app you created on supertokens.io
            ConnectionURI: "http://localhost:3567",
            APIKey:        "",
        },
        AppInfo: supertokens.AppInfo{
            AppName:       "GOInfluencer",
            APIDomain:     "http://localhost:8080",
            WebsiteDomain: "http://localhost:8081",
        },
        RecipeList: []supertokens.Recipe{
            emailpassword.Init(nil),
            session.Init(nil),
        },
    })

    if errr != nil {
        panic(errr.Error())
    }