Greeting over text
Assalamualaikum does one have to reply to salaam over text in a group chat like one has to in person
Wa ʿAlaykumus Salām Wa Raḥmatullāhi Wa Barakātuh
In the case of a group chat, if one group member replies on behalf of the others, that will be sufficient.
If a person greets with the Salām in an abbreviated manner via text messaging, it will not be necessary for the recipients of that message to reply to that since it is, in actual fact, not a greeting. However, if a person has greeted in a full unabbreviated manner and in accordance to how it should be articulated, then the reply should be in the like manner.