Abstract
OBJECTIVES: to describe the construction and validation of a mobile application on sensitive periods of child development. METHODS: methodological research focused on the technological development and validation of software, in the form of a mobile application, conducted from March to October 2023 in two stages: 1) construction of the BASENP mobile application and 2) content and appearance validation by experts. RESULTS: content experts evaluated the material, resulting in a total Content Validity Index of 0.89. Experts in the field of information and communication technology obtained an Agreement Index of 0.86%. The binomial test was not significant for the majority of items in both groups. CONCLUSIONS: the application was developed and validated with methodological rigor and may contribute to improving knowledge and care provided to infants.