Planning Center's API documentation covers endpoints and fields well. What it doesn't cover is the handful of decisions that shape your integration, and those are the ones that hurt to change later. These are notes from building against it rather than a replacement for the reference.
Choose auth before you write anything
A Personal Access Token belongs to a user in one organization and is the right call for a single church. An OAuth application is what you need for something multiple churches install, and Planning Center suggests creating a separate organization to own it.
Pick the second if there's any chance this becomes a product. Migrating a live integration from personal tokens to OAuth means reconnecting every church you've onboarded, which is the kind of email nobody wants to send.
JSON:API means assembly
The API follows the JSON:API specification. Relationships come back as references rather than nested objects, so the response you get is rarely the shape you want to render. Plan on includes and a second pass to assemble a group with everything attached to it.
Pagination and rate limits will find you faster than you expect, particularly if you fetch on page load rather than on a schedule.
Published is a property, not a filter you can forget
Planning Center decides whether a group is publicly visible, and your integration has to respect that on every refresh rather than only at import. A group that gets unpublished should disappear from your site.
The reconciliation problem
This is the part that separates a weekend project from something you can leave running. Creating and updating records from the API is easy. Noticing absence is not.
A group that was deleted or unpublished doesn't announce itself. Nothing arrives to tell you it's gone. You find out by walking the full collection and comparing it to what you're holding, and if you get that logic wrong you either leave ghost pages advertising groups that ended months ago, or you delete live groups because one paginated request failed.
PCO Bridge handles this by confirming missing groups individually after a complete traversal before withdrawing any local copy. Whatever you build, build something deliberate here rather than assuming a failed fetch means deletion.
Check the live docs
Field-level details change, so treat the official API reference as authoritative over any blog post, including this one. What's above is about shape and sequencing, which tends to stay true longer than field names do.
PCO Bridge is in beta and applications are open to churches, developers, and agencies.