JavaScript/Web SDK

For JavaScript, here is the code we recommend for generating, persisting and retrieving a UUID. This could be wrapped in a function can called directly from the PUBNUB.init function rather than the two step inline solution below.

// get/create/store UUID
var UUID = PUBNUB.db.get('session') || (function(){ 
    var uuid = PUBNUB.uuid(); 
    PUBNUB.db.set('session', uuid); 
    return uuid; 

// init PUBNUB object with UUID value
var pubnub = PUBNUB.init({
    publish_key: pubKey,
    subscribe_key: subKey,
    uuid: UUID

Android/Java SDK

For Android, here is the code we recommend for generating, persisting and retrieving a UUID. There is not constructor that accepts the UUID as a parameter, so you must instantiate Pubnub object first then use the setter to provide the UUID.

// creating the Pubnub connection object with minimal args
Pubnub pubnub = new Pubnub(pubKey, subKey);

// get the SharedPreferences object using private mode 
// so that this uuid is only used/updated by this app 
SharedPreferences sharedPrefs = getActivity().getPreferences(Context.MODE_PRIVATE);

// get the current pn_uuid value (first time, it will be null)
String uuid = getResources().getString(R.string.pn_uuid);

// if uuid hasn’t been created & persisted, then create
// and persist to use for subsequent app loads/connections 
if (uuid == null || uuid.length == 0) {
    // PubNub provides a uuid generator method but you could 
    // use your own custom uuid, if required
    uuid = pubnub.uuid();
    SharedPreferences.Editor editor = sharedPrefs.edit();
    editor.putString(getString(R.string.pn_uuid), uuid); 

// set the uuid for the pubnub object