Cemal Kilic developed security hardening and API key management features for the supabase/cli repository, focusing on robust authentication workflows. He implemented asymmetric signing for API keys using JWKs, with a fallback to symmetric signing, and introduced helpers for JWK conversion and JWT generation to streamline key handling. By refining JWKS exposure to publish only public keys and updating key operations to verify-only, he reduced the risk of private key leakage. Working primarily in Go, Cemal applied his expertise in API security, backend development, and cryptography to deliver a well-scoped feature that improved integration and verification processes without addressing bug fixes.