It might be worth to check out alternatives, such as uploading in the background, as you didnt specify in the limitations that a progress bar must be in the foreground view (https://github.com/Rapsssito/react-native-background-actions). Some code could be taken out of the XHR event itself and placed elsewhere. It also might be worth it to see how parallelism affects your benchmarks.(in this case, running multiple request in a Promise.all() context) (there are some know limits to this too, such as simultaneous connections to a server, or the degree of parallelism available)