Authula is an open-source authentication solution built natively for Go, designed to scale with your application's needs. Whether you are building a small service or a complex distributed system, Authula provides a flexible architecture that supports two primary modes of operation: as an embedded library directly within your Go application or as a standalone authentication server for any tech stack. This versatility ensures that you can start small and transition to a centralized auth service as your infrastructure grows without changing your authentication logic.

At its core, Authula leverages a powerful plugin system that allows you to compose your authentication stack precisely as needed. Functionality is entirely modular, meaning you include only what you require, such as email/password authentication, OAuth providers, session management, or multi-factor authentication via TOTP. This approach keeps your project lightweight while ensuring you have access to robust, production-ready features that follow clean architecture and design principles, emphasizing maintainability and testability.

Some of the key features are:

• Flexible Deployment: Choose between library mode for deep integration or standalone server mode for cross-language compatibility.
• Plugin System: Extend the core functionality with a modular system that supports custom routes, hooks, and services.
• Hook Architecture: Inject custom logic at various stages of the request lifecycle, including request matching, handling, and response finalization.
• Native Performance: Engineered for Go, providing sub-millisecond response times and minimal memory footprint.
• Database Support: Built-in support for SQLite, PostgreSQL, and MySQL using standard adapters.
• Type Safety: Leverages Go’s strong typing for consistent configuration and API usage.
• Extensible Security: Includes support for CSRF protection, secure session management, and rate limiting out of the box.
• Event Bus: An event-driven architecture that allows you to trigger business logic based on authentication events.

Operation is seamless regardless of your chosen mode. In library mode, you import Authula into your Go application, gaining full programmatic access to APIs and plugins while retaining complete control over the build process. In standalone mode, you deploy Authula as a central service, using simple TOML-based configurations to manage your auth settings dynamically without requiring recompilation. Its clean, modular structure ensures that it integrates well with existing services without necessitating a complete rewrite of your backend.

Some common use cases include:

• Monolithic Go Applications: Embedding Authula directly into a standard net/http or Chi-based router for seamless user management.
• Microservices Architectures: Running a centralized Authula instance as a standalone identity provider for multiple services written in different languages.
• Edge Deployments: Utilizing the small binary size and memory efficiency for high-performance authentication at the network edge.
• Custom Authentication Workflows: Building complex, highly specific auth flows by leveraging the hook system and custom plugins to integrate with proprietary business logic.