In such artificial intelligence technology era commencing, the Harumanis mango ripeness guide scarcely reaches for predicting its ripening stages. The use of digital support tools for selective fruits in predicting the ripening stages should not be subdued. Instead, the tool is exercising to be accessible by directive users, local farmers, and consumers. Due to these lacks, this preliminary project is a first step to analyse the ripeness stages of Harumanis mango, referring to its firmness, pulp colours, and total soluble sugar (TSS) for digitalization purposes. Twenty-five Harumanis mangoes harvested at week tenth after bloom were used, which had an average mass of 417.96 ± 163.24 g. Five samples were randomly selected and sorted in five stages by settling them under room temperature and a two-day interval. Findings showed the lowest TSS content uncovered at stage 2 for 6.94 Brix and the highest found at stage 5 for 15.02 Brix. The highest firmness unfolded in stage 2 with the value of 28.468 N and the lowest discovered in stage 5 with 7.946 N. In the RGB value scheme, the pulp colours showed a reduction of blue values for 70, activated at stage 3. The results suggested that the Harumanis mango started deteriorating after six days of room temperature storing, followed by rapid firmness degradation and increasing TSS value. Moreover, combinations of RGB colour values, which are red, green, and blue, composed constructive predictive yellowish variants as recorded in the five stages. Positively, the respective RGB values incorporated are useable to develop digital decision-supporting tools such as smartphones.