|Focus||Open Source?||Support?||Availability||Implementation Guide|
|CAQH Endpoint Directory||Payer||No||Yes||Preview|
|CARIN FHIR DIrectory||Payer||Yes||No||GA||No. Flat file.|
|ONC/MITRE Lantern||None||Yes||No||GA||VhDir STU2|
|OneRecord Health Plan Directory for Consumer Apps||Payer, Consumer||TBD||Yes||Proposal|
|FHIR Fly Endpoint Directory||None||TBD||Yes||Preview|
Health Plan API (External)_CARIN Discussion_2021-04-01.pdf
Validated Healthcare Directory (VhDir) FHIR IG should become the canonical implementation guide for exchanging information about directories. However, VhDir is on an STU2 ballot and has not been officially released.
The promise of VhDir is that it will allow servers to write their endpoint details once, and reuse them on any endpoint directory where they want to be listed.