&gt;Legally not allowed? You can donate to anybody you please I would think.<p>Cooperations can probably only donate to 501(c)(3)s without it being considered paying someone off the books or, worse, money laundering by IRS standards.<p>If the project doesn&#x27;t have any ability to send an invoice then they probably aren&#x27;t formal enough for a 501(c)(3).<p>That being said, its only a few clicks to send someone an invoice in PayPal so its a little odd this is a difficult thing for an open source project to do.