<![CDATA[General Background: Digital transformation has become a strategic instrument for bureaucratic reform and public service innovation. However, local governments adopt different approaches shaped by their institutional capacities and governance arrangements. Specific Background Chonburi Province, Thailand, emphasizes horizontally integrated smart city services, whereas Sidoarjo Regency, Indonesia, prioritizes vertically integrated administrative services. Knowledge gap: Despite these developments, comparative evidence explaining how different integration models influence innovation sustainability remains limited. Aims: This study compares digital public service innovation in Chonburi and Sidoarjo to identify lessons for strengthening digital governance in Indonesian local governments. Using a descriptive qualitative comparative case study, the research analyzes secondary data from government documents, institutional publications, media coverage, and scholarly literature through thematic and comparative analysis, guided by the e-government stage model, diffusion of innovation theory, and institutional capacity. Result: The findings show that Chonburi integrates smart city initiatives, including data analytics, environmental risk mitigation, healthcare, waste management, and digital tourism, supported by public–private partnerships. Sidoarjo focuses on digital platforms that simplify licensing and population administration down to the village level. Chonburi demonstrates advantages in cross-sector collaboration and tourism innovation, while Sidoarjo benefits from compatibility with existing institutional structures. Nevertheless, fragmented applications, limited trialability, digital literacy gaps, unequal access, and data security concerns challenge sustainability. Novelty: This study’s novelty lies in explaining how horizontal and vertical integration models interact with institutional capacity to shape digital innovation sustainability. Implication: It recommends strengthening cross-sector data integration, public–private partnerships, phased testing, digital inclusion, and data governance to promote sustainable local digital public services]]>
