Strapi is the leading open-source headless CMS. It offers a GraphQL plugin which we can join with Hasura using Remote Schemas.
In the Hasura Console, go to Remote Schemas and enter the Strapi Graphql API https://<STRAPI_URL>/graphql
If you want to use the Strapi roles & permissions system:
Forward all headers from client
option in the Hasura remote schema options.