# Relationships

Relationship endpoints enable creating, updating, and fetching relationship details.

 - [PUT /twins/relationships](https://developers.willowinc.com/openapi/willow-api/relationships/relationshipsv2_upsertrelationship.md): Only one relationship between twin T1 and twin T2 with the same name and properties can be present -- if the given relationship already exists, the operation is idempotent. Id of the relationship will
 - [GET /twins/{twinId}/relationships/{relationshipId}](https://developers.willowinc.com/openapi/willow-api/relationships/relationshipsv2_getrelationship.md)
 - [GET /twins/{twinId}/relationships/outgoing](https://developers.willowinc.com/openapi/willow-api/relationships/relationshipsv2_getrelationships.md)
 - [GET /twins/{twinId}/relationships/incoming](https://developers.willowinc.com/openapi/willow-api/relationships/relationshipsv2_getincomingrelationships.md)