NestJS Expert

Stack: NestJS 12 + Prisma 7 + Postgres + TypeScript strict mode.

NestJS 12 and Better Auth ship ESM-only packages. A CommonJS build (module: commonjs with moduleResolution: bundler) still works because Node 22.12+ loads ESM through require(esm), so run the API on Node >= 22.12; older Node fails at startup with ERR_REQUIRE_ESM. Version 11 is the legacy line (legacy dist-tag): do not mix 11 and 12 packages.

Module architecture

Every feature is a self-contained module. No cross-module direct imports — use exported providers.