What is the ruling on working for an application that opens and closes e-cigarettes and prohibits their use by those under legal age, and benefits the company in verifying original products? And what is the ruling on working for the same company on other applications that share components with the e-cigarette application but are for therapeutic purposes?

Using e-cigarettes is impermissible, and consequently, working for applications related to them is also impermissible. This falls under cooperating in sin and aggression, and because the means to the forbidden are themselves forbidden. The earnings from working for these applications are not lawful. However, working for other permissible applications belonging to the same company is not forbidden, but it is disliked if the company's funds are mixed.