I run a large contract developer team that's globally distributed. The short answer is that US law permits hiring international contractors who are not subject to US jurisdiction provided they file a W8-BEN executed by that contractor certifying their tax exempt status. These contractors are responsible for paying taxes under their own countries' laws as part of a mutual tax treaty with the US.

Feel free to email me with questions. If you'd rather just hire one of our remote developers and not deal with the paperwork yourself, that's another option. We manage contracts with clients as a US company to insulate them from needing to set up 1-1 relationships with devs.