The best replacement for volley is rally.

The best alternatives to volley are rated as following:
★★★★★  rally
★★★★  retrofit
★★★★  robospice
★★★★  picasso
★★★  okhttp
★★★  asynctask
★★★  aquery
★★  universal image loader
★★  half volley
★★  salvo
  rapid fire

Your alternative for volley is not listed? Suggest!
Speaking about volley, one probably shouldn't forget about okhttp.

Other search terms related to volley and their ratings are:
★★★★★ okhttp
★★★★ gson
You have in mind a companion for volley and it is not yet here? Propose!



Google Trends

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volley
rally
retrofit