var el = document.createElement("script");
el.async = true;
el.defer = true;
el.src = "https://cdn.jsdelivr.net/npm/[email protected]${version}/dist/oneaccount.min.js";
document.body.appendChild(el);

<script defer async src="https://cdn.jsdelivr.net/npm/[email protected]<version>/dist/oneaccount.min.js"></script>

if (window.oneaccount) {
  initOneaccount();
} else {
  document.addEventListener("oneaccount-loaded", initOneaccount);
}
​
// init the library
function initOneaccount() {
  window.oneaccount.init("your external id", {
    // NOTE: Please check the Library options page for more customisations
    iOSRedirectURL: "/user", // required
    callbackURL: "/oneaccountauth", // required
  });
}

<!-- NOTE: the classes are important for the library to attach the click bindings -->
<button class="oneaccount-button oneaccount-show">Sign in/up using One account</button>

document.addEventListener("oneaccount-authenticated", function(event) {
  // data contains any data you have returned from the backend
  var data = event.detail;
  // your business logic here
});

package main
​
import (
	"encoding/json"
	"net/http"
	"os"
​
	"github.com/go-redis/redis/v8"
	"github.com/oilastudio/oneaccount-go"
)
​
func main() {
	var redisClient = redis.NewClient(&redis.Options{})
	
	oa := oneaccount.New(
		// If engine setter and getter are not set an in-memory engine will be used. 
	  // For production it is recommended to provide an engine setter and getter:
  	// for this example we will use redis but any other storage could be used
  	oneaccount.SetEngineSetter(func(ctx context.Context, k string, v []byte) error {
			return redisClient.Set(ctx, k, v, 3 * time.Minute).Err()
		}),
		oneaccount.SetEngineGetter(func(ctx context.Context, k string) ([]byte, error) {
			v, err := redisClient.Get(ctx, k).Result()
			if err != nil {
				return nil, err
			}
			return []byte(v), redisClient.Del(ctx, k).Err()
		}),
	)
	
	// The route URL is the callback URL you have set when you created One account app.
  http.Handle("/oneaccountauth", oa.Auth(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
    // NOTE: never return code 200 if a user is not authenticated
		if !oneaccount.IsAuthenticated(r) {
			http.Error(w, "something went wrong while authenticating, please try again later", http.StatusInternalServerError)
			return
		}
		// a user is authenticated and you can implement any logic your application 
	  // needs. oneaccount.Data(r) returns the data sent by the user 
	  // after successful authentication.
	  
	  // since One account doesn't differentiate between sign up and sign in, 
	  // you can use userId to check if the user signed up c on your website or not.
	  // the same way you can access any other data you requested from the user:
		type User struct {
			FirstName string `json:"firstName"`
			UserID    int    `json:"userId"`
		}
		
		var data = user{}
		if err := json.Unmarshal(oneaccount.Data(r), &data); err != nil {
			http.Error(w, err.Error(), http.StatusBadRequest)
			return
		}
		// any data returned here would be sent to oneaccount-authenticated event on front-end e.g.:
		w.Header().Set("Content-Type", "application/json; charset=utf-8")
		json.NewEncoder(w).Encode(data)
		// NOTE: handle the error
	})))
}