Developed and delivered a certificate Subject Alternative Name (SAN) extraction feature for the external-secrets/external-secrets repository, enabling dynamic templating based on DNS names, IP addresses, emails, and URIs parsed from PEM-encoded certificates. The work focused on backend development using Go and YAML, integrating SAN extraction into the templating system to automate certificate management and reduce manual configuration. Comprehensive tests and documentation were included to ensure reliability and minimize misconfiguration risks. Collaboration with other contributors aligned the feature with broader PKI and secret-management initiatives, enhancing automation and security posture while demonstrating strong skills in templating, testing, and backend engineering.