During May 2025, Bassberry Juice developed a security-focused authentication feature for the evcc-io/evcc repository, enhancing Toyota API integrations. Leveraging Go for backend development, Bassberry implemented HMAC-SHA256 based authentication, introducing a client reference header and a per-request digest generated from the vehicle UUID and client secret. This approach improved request integrity and security, while the addition of an app version header enabled better traceability and debugging for API calls. The work demonstrated depth in API integration and cryptography, addressing both security and maintainability. Although the contribution was limited to a single feature, it provided robust, targeted improvements to the codebase.