Worked on the better-auth/better-auth repository to enhance security around API key validation and configuration integrity. Focused on hardening the api.verifyApiKey function so that API keys are validated strictly against their associated configId, effectively preventing cross-configuration key usage and reducing the risk of unauthorized access in multi-tenant environments. The solution was implemented in TypeScript, leveraging skills in API development, error handling, and testing to ensure robust and reliable code. Maintained clear, well-documented commits and collaborated efficiently to improve traceability and code review processes. This work addressed a critical security concern by fixing a bug rather than introducing new features.