RNA therapeutics have evolved from passive genetic intermediaries into highly programmable platforms, fundamentally transforming the landscape of precision medicine. This comprehensive review examines the molecular architecture and mechanisms of established platforms in the clinical setting, including mRNA, antisense oligonucleotides (ASOs), small interfering RNAs (siRNAs) and aptamers, alongside next-generation platforms, such as CRISPR-guided systems and circular RNAs (circRNAs). Moreover, we discuss strategies to overcome systemic delivery bottlenecks and evaluate advanced non-viral systems, emphasizing lipid nanoparticles (LNPs), polymers and tissue-specific ligand conjugates that facilitate precise intracellular targeting. Furthermore, we explore the clinical expansion of these platforms across infectious diseases, rare genetic disorders, oncology and cardiovascular conditions. Finally, we highlight how the integration of artificial intelligence (AI) and machine learning (ML) redefines the limits of individualized, programmable RNA therapies by accelerating sequence optimization and nanoparticle formulation.