We make it super simple to upload large lists. You can use either .CSV or VCards files. Keep in mind you can only use custom variables with .CSV though.
When you upload your contacts files, BurstSMS will automatically sek out duplicate numbers and remove them. It will also do the same each time you upload a new file so you can keep one master list without worrying about sending the same message to the same person.
When you upload a file, you will be asked to map your fields, here you will see each column in your file and be able to match it with the fields in your BurstSMS list.
When you upload a list, BurstSMS can automatically format the numbers into the correct format based on the country you select. If you are sending messages to multiple countries, you will need to have all of the numbers formatted with their correct country code. In this case do not select a destination country.