Worked on the fleetdm/fleet repository to resolve a backend issue affecting SCEP PKIOperation payload decoding, which previously caused 400 errors during device enrollment. Addressed the root cause by ensuring correct handling of '+' characters in base64 payloads, which were mistakenly interpreted as spaces. Enhanced the Go backend by adding regression tests that verify both literal and percent-encoded '+' in query messages, thereby preventing future regressions. Focused on backend development, API reliability, and comprehensive testing, these changes stabilized the SCEP enrollment flow for macOS devices, reduced error rates, and improved the reliability of device onboarding and fleet provisioning processes.