During May 2025, Taavi Aavik focused on backend reliability in the tailscale/tailscale repository, addressing a nuanced issue in OIDC and OAuth 2.0 authentication flows. He delivered a targeted bug fix in Go, ensuring that empty refresh tokens were omitted from token exchange requests, thereby aligning the implementation with protocol standards. This change, applied to the cmd/tsidp component, reduced token-exchange errors and improved interoperability with various identity providers. By concentrating on protocol compliance and error resilience, Taavi’s work enhanced the reliability of authentication across deployments. His contributions demonstrated depth in backend development, OAuth, and OIDC protocol handling.