Slow upload speed to storage.

[LuMa1]

Hello,

I upload files on my storage bucket using a signed url. 

To do so, I use axios from my VueJs app with a PUT request. My bucket is multi-region (eu) and my users are in europe too.

Everything works fine except for users on mobile phones or with not so good connections desktops. It takes about 60s to upload a 10Mo file from these devices. 

Do you see any improvement i can try to decrease this time to upload a file ?

[KirTitievsky]

It seems like you have reasonable evidence that this upload speed is determined by the bandwidth available to the device, not GCS.  This is worth confirming, by for example, doing a speed test on the browser on the device.   If it's in fact the bandwidth the only way to speed this up is to reduce the number of bytes you send. So perhaps try compressing the files before sending them? This might help on the download side: https://cloud.google.com/storage/docs/transcoding