Recent studies show that texting-based interventions can produce educational benefits in children across a range of ages. We study effects of a text-based program for parents of kindergarten children, distinguishing a general program from one adding differentiation and personalization based on each child’s developmental level. Children in the differentiated and personalized program were 63 percent more likely to read at a higher level (p<0.001) compared to the general group; and their parents reported engaging more in literacy activities. Effects were driven by children further from average levels of baseline development indicating that the effects likely stemmed from text content.