ISSUE ADDRESSED: Type 2 diabetes (T2D) prevalence in Thailand is rapidly increasing, with significant challenges in achieving optimal glycemic control. There is a need for accessible interventions to help improve glycaemic control in people with type 2 diabetes in Thailand. This study evaluates a web application designed to enhance self-management in individuals with uncontrolled T2D. Pre- and post-intervention results indicate a statistically significant reduction in fasting blood glucose. Despite the inability to effectively utilise the web application for controlling blood sugar levels, the study suggests its suitability and potential for benefiting diabetes patient care. BACKGROUND: Diabetes is a rapidly growing global health concern, with an estimated 537 million people affected worldwide in 2021, a number projected to rise to 783 million by 2045. In Thailand, diabetes cases have increased significantly, with over 3.3 million individuals affected in 2022. Effective diabetes management requires strict adherence to self-care behaviors, including diet, exercise, medication adherence, and glucose monitoring. However, many patients struggle with self-management, leading to severe complications. The integration of a web application in diabetes care has shown potential for enhancing patient engagement and glycemic control. This study explores the role of a web application in improving diabetes self-management and health outcomes. METHOD: The quasi-experimental single-group research, assessing pre- and post-intervention outcomes, aims to investigate the feasibility of using a web application for diabetes patient care in controlling blood sugar levels. The study employs a web application focusing on dietary behaviour adjustment, physical activity and exercise among 80 diabetes patients selected through simple randomisation. Additionally, 10 nurses responsible for healthcare promotion at five hospitals oversee and empower patients' behaviours over two months. The research concentrates on exploring the feasibility of the web application and includes (I) the application's suitability and (II) the patient's blood sugar levels. The research collected quantitative and qualitative data from November 2022 to May 2023. Tools used for data collection include the feasibility assessment and application suitability. RESULTS: The research findings indicate that the primary assessment regarding the feasibility of using the web application for diabetes patient care in controlling blood sugar levels shows overall high feasibility. The overall assessment also falls within a high range. Comparing the average levels of fasting blood sugar (FBS) before and after using the web application showed a statistically significant decrease (p-value = 0.023). When comparing the average FBS levels before and after using the web application among diabetes patients, the average FBS decreased significantly from 157.07 ± 47.248 mg/dL to 150.00 ± 43.325 mg/dL (p = 0.023). However, the HbA1c levels showed no statistically significant change (9.17% ± 1.76 to 9.12% ± 1.82, p = 0.38). SO WHAT?: These outcomes may positively contribute to early effective interventions and as well as appropriate responses to diabetes mellitus. Further supported for the health care professionals the use of a web application for diabetes patient care in patients with poorly controlled blood sugar. Specifically, for patients with smartphones, this intervention could help address their issues and provide tools for better self-regulation of their eating habits, physical activities and overall well-being. This can lead to better blood sugar control efficacy.