Saving data with HttpService?

You shouldn't be using HttpService for something like this. Instead, use DataStores. To save a table value with HttpService, simply do something like

datastore:UpdateAsync("Example",function(old) -- make sure it's a table
    if type(old)~="table" then
        return {}
    end
    return old
end)

From then on, you can do:

datastore:UpdateAsync("Example",function(old)
    old[whatever]=whatever2
    return old
end)

Remember to almost never use SetAsync unless the data saved before does not matter.