I have a cryptocurrency data-providing website. Now I want to enable a feature that allows members to set price alerts for a specific cryptocurrency i.e. whenever the price reaches the threshold limit set by the user itself, the system automatically sends an email providing the necessary data. I have set the APIs and the code that fetches all the data. So, is it possible that the system will fetch the data and do the alert work even when the user is not using the website? How can I make this feature possible? I am working on this website for almost 8 months and this feature is a turning point for my website. Please guide me through this.