Most Membership.io endpoints return JSON:API-style documents.
Use this request header:
application/json is also accepted by the backend for compatibility, but application/vnd.api+json is the canonical media type.
Resource response
A single resource response has data.id, data.type, and data.attributes.
List response
A list response returns data as an array. Paginated endpoints also include links and metadata.
Write request
Many newer write endpoints use a JSON:API envelope:
Some alpha endpoints still accept flat request bodies or return flat token bodies. Check the generated OpenAPI page for the exact endpoint before building a client.
Errors
Errors return an errors array. Each error has an HTTP status string, title, detail, optional code, and optional source pointer.