Reducing launch time in HTML5 project

Hello everybody,

I’m a newbie on UE4 and I’m working on a project for HTML5 development.
The project is simple : It’s just a little map with some foliage and an house at the center. People can click on differents parts of the house to have got informations in popups. It’s not a game with full effects…
When I deploy the project on HTML5 on Chrome with UE4, I’ve got a downloading time of only 5 seconds ! cool ! but after I’ve got a long long time of ‘compiling web assembly’… But for the project I must keep the starting time under 10 seconds.

Do you have some tips or solutions to reduce or erase this ‘compiling web assembly’ time ?
Thank you by advance for your help.