Curious to know how many characters (and therefore bytes) your push notification contains?
Check out the handy website below for more information:
According to the iOS Local and Push Notification Programming Guide:
The maximum size allowed for a notification payload is 256 bytes; Apple Push Notification Service refuses any notification that exceeds this limit.
This means that the actual text that is displayed as a push notification depends on how much text is taken by the other components in your push notification request (like URL length, custom buttons etc.). Also, iOS does not define how much maximum text you can display on the screen and how it gets formatted. Because different characters take up different amounts of space in a line of text, this makes it difficult to predict how your message will be shown.
As long as your entire payload is less than 256 bytes and the message text is less than 236 characters (this is what is left after the minimum required payload is included) this page will show you how your message will display.