How text credits work
Text credits allow you to send text messages. You can consider text credits to be the currency used on EchoBack to pay for the sending of texts. A simple short text message will require only one credit. A text of 160 characters can be sent with just one credit. When you exceed 160 characters you will use additional credits to send the text. Be aware that special characters such as emoji can lead to increased credits
being used. Although a text of 160 characters will only require one text credit, a text of twice that amount, 320 characters, will actually require 3 text credits. This is where things get tricky. When lengthy texts are sent the sending phone actually has to send multiple linked-together 160-character texts. The receiving phone is responsible for stitching the texts together into one long text. The information needed to maintain the order of the sent texts takes up some of your 160 character spots for each segment. A 161 character text will actually be sent as one 153 character text and one 8 character text. The information to keep texts in order took up 7 characters of the first text segment. When you send longer texts this repeats for each new segment of 160 characters. So although one text is 160 characters, multiple texts are actually only 153 characters each. Now that your multi-part text is constructed these credits will be used for each contact you send a text to. Each app page calculates how many credits will be used for each message, before you send it.