Are they compatible with your existing site software?
First and foremost, you need to figure out which payment systems are supported by any third-party software that you use on your website, like Wild Apricot, Shopify, or Cvent. If they’re not compatible with your existing setup, you won’t be able to use them without changing your software.
Do they support merchants in your country?
Another easy way to chop down your list of possible payment partners is to eliminate those that don’t support organizations operating in your country. Several payment providers such as Authorize.Net, BluePay, Global Payments, and Moneris require you to have a merchant account in the United States or Canada, and Google Wallet is available only to merchants in the US. If your organization is based in the UK, then you can count Shrill, IATS, and PayPal among your options.
Do they support the currency you want to use?
If the members and supporters of your organization are concentrated in a particular country, you should make sure the payment providers under consideration support the currency you want to use in your transactions. Most support a wide range of currencies, but BluePay and Global Payments support only US and Canadian dollars, while Authorize.Net and IATS support British pounds as well. Google Wallet supports only US dollars and British pounds. In contrast, 2Checkout, Moneris, Shrill, and PayPal all support dozens of different currencies.