Interceptors
Aspect-oriented programming with interceptors for cross-cutting concerns like logging, caching, transformation, and timing.
Event System
Type-safe, auto-discovered event system for decoupled architecture.
Guards & Authorization
Comprehensive guard system for authentication and authorization.
Authorization Setup
Wire up the v4 authorization subsystem with one call - permission hierarchy, caching, preloading, and your AuthProvider.
Lazy Loading
Zero-config lazy loading with auto-detection, warmup strategies, and performance optimization.
Testing Module
Comprehensive testing utilities for unit, integration, and E2E testing.
Logging System
Production-ready logging with 11 comprehensive phases including structured logging, transports, redaction, monitoring, and query capabilities.
Enhanced Configuration
Type-safe configuration management with validation and environment switching.
Middleware
Middleware are interceptors.
Decorators
Reference for every decorator shipped by ExpressoTS v4: DI, controllers, methods, parameters, validation, content negotiation, AOP, security, events, and lifecycle.
Status code
Use the StatusCode enum to set HTTP status codes consistently across controllers, use cases, and errors.
Error handling
Error handling in ExpressoTS v4: typed app errors, RFC 7807 problem details, exception filters, and the Report helper.
Render engine
How to render views in ExpressoTS.
ExpressoTS config
ExpressoTS configuration file.
DTO validator
Use the v4 validation system with class-validator, Zod, or Yup for DTO payload validation.
Env validator
Validate environment variables in v4 with defineConfig + Env.* and loadEnvSync.
DB in memory
A Prisma-like in-memory database for development, testing, and prototyping.
Content Negotiation
RFC 7231-compliant content negotiation in ExpressoTS v4. Accept / Consumes / Produces decorators, built-in JSON / XML / CSV / YAML / plain-text formatters, and streaming responses.
Validation
ExpressoTS v4 Smart Validation: Zod, Yup, class-validator, and custom adapters via a single registry and parameter decorators.
Exception Filters
Customize how ExpressoTS turns errors into HTTP responses with @Catch, @UseFilters, and BaseExceptionFilter.
Route Patterns
Type-safe regex constraints on route parameters using Patterns and pattern(): Express 5 / path-to-regexp v8 compatible.
API Versioning
Run multiple API versions side by side using @Version, with controller-level or method-level overrides.
Health & Monitoring
Built-in middleware health endpoint, IHealthCheck providers, and the aggregated health dashboard.
OpenAPI Spec Generation
Generate an OpenAPI 3.1 document from your ExpressoTS app with zero annotations, enrich it with real traffic, detect spec drift, and keep clients in sync.