How to exclude the possibility of hacking on the site?

Question

HTML

Hello, I got a very anxious client who is concerned about the security issue.

The task is very simple, there will be a landing page (html + css + js) without any executable code (maximum sending letters to php). On the html page, a code (plain text) will be written, which no one should change in any case, otherwise a terrible thing will happen.

A large load is planned on the site (tens of thousands of people per day, and maybe per hour). Also, the customer promises not isolated cases of hacking attempts.

Actually questions:
1) In vain does the client worry at all?
2) Is there a need for https?
3) Do I understand correctly that in this case everything depends on the security of the host?
4) Advise, if you know, good hosters that can provide security and high load on the page.

Answer 1

And what will they break? Static landing? There is nothing to break there.
Therefore, the hosting itself will be broken. Here all the questions are for the hoster, and if it is shared hosting, then Petya's neighbor can be broken, and in addition, it will fly to you.
If you are so afraid of changes in the landing page - as an option, download it with wget at least once a minute and read crc on any other machine, turn on the siren if necessary.