How do I know a customer has read my WhatsApp order update?

Each message reports a status. On the API: sent (one tick), delivered (two ticks), read (two blue ticks) or failed. Read means it was shown in an open chat.

• A message counts as read only after it was delivered.
• If the customer opens the chat straight away, the delivered status may be skipped.
• A failed status means the message never reached the phone.
• Check the status before you resend an update, so the customer is not messaged twice.