Zeffy relies entirely on optional tips from your donors. When making a payment on a Zeffy form, your donors can choose to contribute to Zeffy or not. On average, 2 out of 3 donors leave us a tip. This is enough to cover all our costs and re-invest in the development of Zeffy. Zeffy has been working with nonprofits for 7 years and, thanks to this 100% free model, currently supports 100,000 organizations across North America.