Planning Center offers a single API to give you access to data from Check-Ins, People, and Services, with plans to add APIs for our other apps in the future.
The #api channel in our Slack community is dedicated to discussing API usage with other third party developers.
If you have any questions or run into any hiccups, please open open an issue on our developer repo.
Planning Center Online is a development driven company - over half of our staff are either developers or designers (designers who code!), our owner spends most of his time developing, and our developers maintain several popular open source projects and have contributed to many others including Rails and RSpec.
If you're a like minded developer, take a look at our careers page.