Gorush is a push notification microserver written in Go that delivers notifications to iOS (APNS), Android (FCM), and Huawei (HMS) devices. It exposes both an HTTP REST API (built with Gin) and a gRPC interface for high-performance integration. The system is designed for production use with configurable queue backends (local in-memory, NSQ, NATS, Redis), multiple workers, and pluggable statistics storage (memory, Redis, BoltDB, BuntDB, LevelDB, BadgerDB). It supports concurrent iOS push limiting, automatic retry on failure, feedback webhooks for asynchronous error reporting, and Prometheus metrics for monitoring. The architecture follows a clean producer-consumer pattern: incoming push requests are validated and enqueued, then processed asynchronously by workers that dispatch to platform-specific push services. The codebase is well-structured with clear separation of concerns across packages (app/, config/, core/, notify/, router/, rpc/, storage/, logx/, metric/, status/). It includes comprehensive test coverage, CI/CD pipelines, Docker/Kubernetes/AWS Lambda deployment support, and security scanning. The configuration system uses Viper with YAML files and environment variable overrides, with built-in validation and sensitive field redaction for safe API exposure.