BYO (Bring Your Own) Auth enhances existing authentication systems without requiring migration. It offers advanced features like session management, enterprise single sign-on (SSO), SCIM provisioning, and support for passkeys, all deployable as a self-hosted sidecar. This setup allows companies to integrate these capabilities alongside their current authentication methods, whether developed in-house or sourced from third parties. Key features include session management that protects against session theft and tracks new devices or IP changes. User impersonation enables support teams to assist customers more effectively by stepping into their accounts. The platform integrates with popular identity providers like Okta and JumpCloud, streamlining SSO processes. SCIM provisioning automates user management between identity providers and applications, while passkeys offer a passwordless authentication option, reflecting a shift away from traditional passwords. Built with Rust, BYO Auth emphasizes speed and low resource consumption. It allows organizations to maintain control over user data by deploying the solution on their own infrastructure. The management dashboard simplifies troubleshooting and configuration, enabling teams to reset passkeys and monitor session activity. JSON-formatted logs facilitate debugging, making it easier to trace user interactions and issues. The service is adaptable to various environments, including on-prem solutions, and aims to support even the most complex user challenges.