Mercurius Auth Plugin

Mercurius Auth is a Fastify plugin designed to add configurable authentication and authorization support to GraphQL APIs built with Mercurius. It is currently at stable version 6.0.0, with major updates often aligning with new Fastify or Mercurius versions. The plugin allows defining auth directives directly within the GraphQL schema to apply custom policies against protected fields, supporting both normal and gateway modes. Alternatively, it can operate in an 'External Policy' mode, offering programmatic control over authorization. Key differentiators include its tight integration with the Fastify and Mercurius ecosystems, its ability to build an auth context, and its GraphQL spec compliance, including features like schema filtering and replacement. Development appears active, with regular updates and dependency bumps.