I hope you already know that websites hosted at 00web host sleep for one hour daily and your free to choose the time it will sleep in your account settings.
We try however we can to power all the websites on this free/learning platform but sometimes you can notice some little bit of down times on numerous occasions but they are always Minor.
depending on the load that your website is experimenting you could consider a DDoS solution for your website or even a cloudflare like would be a nice to have for those peak of traffic that you might encounter.