As mentioned in the Introduction, pygeoapi strives to implement the OGC API standards to be compliant as well as achieving reference implementation status. pygeoapi works closely with the OGC CITE team to achieve compliance through extensive testing as well as providing feedback in order to improve the tests.
The pygeoapi CITE instance is at https://demo.pygeoapi.io/cite
Setting up your own CITE testing instance
Please see the pygeoapi OGC Compliance for up to date information as well as technical details on setting up your own CITE instance.