Petros Kyriakou yes exactly, also doing validation/transformation through class-validator/class-transformer, but validation is also possible in the official NestJS config module through Joi like you outlined in your great article :)

Glad to see someone else had the same requirements in regards to managing environments and environment variables in NestJS. What we ended up using was nest-typed-config with its multiple loaders approach. Basically we have 4 different config files: base.yml (shared across all environments) development.yml test.yml production.yml We still leverage the env var loader with highest precedence to adhere to 12factor principles, while providing sane defaults to ease the setup and being developer friendly.