Google Maps Api Max Request Using only one Api Key (is it per device or per api key)

Question

We want to build an application with embedded gmaps . It is said in condition in this question Google Maps API, do I need to buy? that only 2500 request max are free otherwise we need to pay for it . Part of the answer is that there is a max request of 2500 PER DEVICE PER DAY. What if I have 10 device using 1 ApiKey, is it still 2500 per device per day or 2500 for all 10 devices per day that I need to divide as 250/device to cater 2500 for all?

My use of the API is that I use the geocoder to decode the address. If I am right, map is free and location of latitude and longitude is free from gps. What I need to check for count of access is the geocoder to decode the address; it means that I can only decode 2500 address (that's why the question is, is it 2500 decode address per device or 2500 decode address for all per day)

UPDATE TO ADD QUESTION

Am I correct that If I use this code to decode the address, I am trying to connect to google maps api that has a limit of 2500 request per day?

    async Task<Address> ReverseGeocodeCurrentLocation()
    {
        try
        {
            Geocoder geocoder = new Geocoder(this);
            IList<Address> addressList =
                await geocoder.GetFromLocationAsync(LocationObject._currentLocation.Latitude, LocationObject._currentLocation.Longitude, 10);

            return addressList.FirstOrDefault();
        }
        catch (System.Exception e)
        {
            throw;
        }
        return null;
    }

Answer 1

From my experience, I think the answer is per your Google Account. That means If you use one google account and generate many keys or using for many devices, total all of them will be 2500.

You can check your request usage via https://console.developers.google.com/ on Dashboard