National identification numbers (NIN) and similar identification code systems are widely used for uniquely identifying individuals and organizations in Finland, Sweden, and many other countries. To increase the general understanding of such techniques of identification, openly available methods and tools for NIN analysis and validation are needed. The hetu and sweidnumbr R packages provide functions for extracting embedded information, checking the validity, and generating random but valid numbers in the context of Finnish and Swedish NINs and other identification codes. In this article, we demonstrate these functions from both packages and provide theoretical context and motivation on the importance of the subject matter. Our work contributes to the growing toolkit of standardized methods for computational social science research, epidemiology, demographic studies, and other register-based inquiries.