I built a PostgreSQL extension in Rust (pgrx) that lets you call gRPC services from SQL.

SELECT * FROM grpc_call('user-service:50051', 'GetUser', '{"id": 123}');

Use case: trigger external services from triggers/functions without leaving the database - no application layer needed.

v0.1.0 - currently uses gRPC reflection only. Next up: proto+connection caching, manually loading port files

Still early - feedback on the API and what you'd actually use this for would be great.