This Happi Exchange Rates service provides a real-time JSON API for 1400+ World Currencies and Cryptocurrencies. Happi.Dev provides various APIs for developers and accepts PayPal or Bitcoin for payments.
The following is a list of SDKs from our SDK directory that matched your search term. Though your definition of an SDK may differ, in our world, we define SDKs as platform- specific tools for consuming existing APIs of the sort we list in our API directory. For example, the Ruby SDK for consuming the Twitter Ads API. If you think an SDK, API, or other asset is missing from our directory, be sure to check our guidelines for making contributions to ProgrammableWeb.