Aim: The main purpose of this feasibility study was to estimate compliance and acceptability rate of a 9-Steps mobile app preparation program. Subsequently, to assess its impact regarding attitudes towards smoking cessation. Methods: The program was only available on versions above iOS 13.3. The ecological study collected user’s data via the app from 04/07/2021 to 28/07/2021. Results: A total of 2331 ecological users completed onboarding; 1926 users (73.9%) completed the step 0 and only 265 users continued in step 1. On average, participants actively engaged with intra-steps activities (85,1%). Most users were highly satisfied at the end of each step. On average 86% found the content of each step comprehensive and relevant. Mann-Whitney tests demonstrated positive changes in attitudes toward smoking cessation on the less confident users: willing (3 to 5, p <.05); confidence (3 to 5, p <.001) and readiness to quit (3 to 5, p <.001). Conclusions: This ecological study corroborates the expected dropout between first use and regular use of health mobile apps. However, engagement and satisfaction rates support the feasibility and acceptability of a 9-step preparation program. Additional research is needed to better understand determinants of regular use of mobile apps and its impact on the target behavior.