HPSF Events Calendar TEC v1 API
The newer Events Calendar tec/v1 REST API on hpsf.io - an OpenAPI 3.0.4 contract with 17 operations over events, venues, organizers and recurring series, with named operationIds, declared BasicAuth and machine-readable pagination. The vendor marks these endpoints experimental and the installation enforces it: an anonymous GET without the acknowledgement header returns HTTP 400 missing_experimental_endpoint_acknowledgement, and /series returns 401. Recorded because the contract and the routes are published, not because they answer anonymously.