Worked on the grafana/grafana repository to address a critical issue in the OAuth login flow, focusing on backend development and API reliability. Implemented a fix that ensures redirect URLs containing special characters are properly handled by URL-encoding the redirectTo cookie, preventing corruption in accordance with RFC 6265 cookie rules. This change improved the reliability and security of authentication redirects, particularly for users with complex PromQL label matchers. The solution was developed in Go, thoroughly tested against existing OAuth flow tests to prevent regressions, and co-authored before being merged into the main branch, reducing user-reported login issues related to redirects.