Free course · 11 lessons · Intermediate
NestJS in Production
Build and run NestJS 12 services that stay maintainable: modules and dependency injection, DTO validation, domain errors and exception filters, guards and roles, interceptors, validated configuration and dynamic modules, testing with the testing module, transactions, request context without request-scoped providers, and lifecycle hooks for clean shutdown. Every example is a real NestJS app, compiled and called over HTTP.
1. Structure, Validation and Errors
Modules and dependency injection, validation pipes, exception filters, guards and interceptors: the building blocks of a maintainable NestJS service.
- Modules, Providers and Dependency Injection — Organise a NestJS service into feature modules, inject providers through constructors, and swap implementations with custom providers.
- Validating Input with DTOs and ValidationPipe — Validate and transform request bodies with class-validator DTOs and a global ValidationPipe that strips unknown fields.
- Domain Errors and Exception Filters — Throw domain errors from services and map them to HTTP responses in one exception filter, with consistent error bodies.
- Authentication and Role Guards — Protect routes with guards: an authentication guard that identifies the user and a roles guard driven by route metadata.
- Interceptors: Logging, Response Shaping and Timeouts — Wrap handlers with interceptors to measure timing, shape responses consistently, and fail slow requests with a timeout.
2. Configuration, Testing, Data and Operations
Validated configuration with dynamic modules, fast tests with the testing module, transactions, request context, and clean startup and shutdown.
- Validated Configuration and Dynamic Modules — Load configuration once, validate it at startup, and provide it through a dynamic module with forRoot().
- Testing with Test.createTestingModule — Write fast unit tests by overriding providers in a testing module, and end-to-end tests that call the HTTP layer.
- Transactions Across Repositories — Keep multi-step writes atomic: a transaction helper that services use, so a failure leaves no half-written data.
- Request Context Without Request-Scoped Providers — Request-scoped providers recreate whole dependency chains per request; AsyncLocalStorage carries a request ID and user cheaply.
- Lifecycle Hooks, Health and Graceful Shutdown — Open and close resources at the right time with lifecycle hooks, and let NestJS shut down cleanly on SIGTERM.
3. Capstone
Design a production NestJS service.
- Capstone: A Subscriptions Service in NestJS — Design a NestJS service for subscriptions and invoices: module boundaries, validation, auth, transactions, testing and operations.