CASE STUDY — FULL STACKBookTomb

What it is

Key challenges

1. 01Prisma 7's breaking changes: the prisma-client generator emits ESM by default, which crashes a CommonJS NestJS app — solved by pinning moduleFormat="cjs" and runtime="nodejs" and moving to a multi-file schema folder with one .prisma file per module.
2. 02Prisma 7 requires an explicit driver adapter, so the Prisma service had to be rebuilt on @prisma/adapter-pg + pg rather than relying on the implicit engine connection.
3. 03Making deduplication safe under concurrency without a distributed lock — the (sha256, uploaderId) unique index is the lock, and the insert conflict is itself the deduplication signal.
4. 04Keeping the domain layer genuinely framework-free: no NestJS decorators, no Prisma types, no argon2 imports — forcing every dependency through ports and mappers at the infrastructure edge.
5. 05Upstash exposes one Redis database over both REST and TCP; the health check uses REST while BullMQ needs TCP, so the REST token had to be documented as doubling as the TCP password.
6. 06@nestjs/schedule shipped an ESM-only release that broke the CommonJS build — resolved by downgrading to the last CJS-compatible version.

Key achievements

1. 01Designed and shipped a strict Clean Architecture backend — four layers per module (domain / application / infrastructure / presentation) with ports modelled as abstract classes that double as DI tokens, and a composition root per module.
2. 02Built JWT authentication with refresh-token rotation, token families and reuse detection: replaying a already-used refresh token invalidates the entire token family.
3. 03Implemented an upload-intent flow with per-uploader content deduplication keyed on (sha256, uploaderId), using the database's unique constraint itself as the lock instead of an application-level mutex.
4. 04Shipped a global rate-limiting policy (120 req/min) with tighter per-route caps for login, registration and upload-intent, exempting the health endpoint so uptime monitors are never throttled.
5. 05Authored a complete documentation set — per-module READMEs, architecture/testing/documentation conventions, Docker and database operations guides, plus a learn-by-doing lesson series for the identity module.
6. 06Wrote a 1,600-line hand-authored OpenAPI 3.0.3 specification as the single source of truth for the API, with inline examples per response and shared error envelopes — importable directly into Apidog.

Technologies used

• TypeScript
• Jest
• REST API design
• OpenAPI
• Clean Architecture
• Node.js
• PostgreSQL
• NestJS
• Prisma
• JWT
• Redis
• Docker
• Cloudflare R2