When looking for synonyms for "back at you," there are a few options to consider. One option would be "same to you," which means the same thing in a more concise way. Another option might be "likewise," which can also convey a similar meaning. "Return the favor" or "return the gesture" could also work, depending on the context. Additionally, "reciprocate" or "reflecting back" might be other options to consider. In any case, the key is to find a phrase that conveys the same meaning in a way that feels natural and fits well within the context of the conversation.