A modular NestJS + TypeScript starter for building AI-powered SaaS REST APIs. This project demonstrates:

• API key based auth and lightweight user/account model
• Image generation endpoints integrating with external AI APIs (e.g., OpenAI, Replicate) - Soon custom fine-tuned model
• Prisma ORM for schema, migrations, and queries
• Clean module separation and DI-friendly services

• 🖼️ Image generation endpoints integrating with external AI APIs (e.g., OpenAI, Replicate) - Soon custom fine-tuned model
• 🔐 API key authentication and usage tracking
• 🗄️ Prisma ORM for schema, migrations, and queries
• 🧩 Clean module separation: controllers, services, DTOs, guards
• 🧪 Unit + e2e tests with Jest and supertest
• ⚡ Ready for local dev and production deployment

• Realistic, extendable baseline for SaaS APIs that need per-client API keys and usage tracking
• Pattern examples: feature modules, DTOs, guards, providers, and Prisma integration
• Practical image-generation flow (upload/init image, prompt, return asset URL)

• Quickstart
• Environment
• Endpoints
• Project structure
• Prisma schema & DB
• Testing
• Common issues & troubleshooting
• Contributing / License

1. Install deps: pnpm install

2. Add environment variables (.env)

   • REPLICATE_API_TOKEN=...
   • DATABASE_URL="file:./dev.db" (or your PostgreSQL URL)
   • PORT=3000
   • APP_API_KEY_SECRET=your-signing-secret (See "Environment" section below for full list.)

3. Run prisma migrations (dev) pnpm prisma migrate dev --name init

4. Start dev server pnpm run start:dev

5. Run tests pnpm run test pnpm run test:e2e

• PORT (optional) — server port
• DATABASE_URL — Prisma connection string
• REPLICATE_API_TOKEN — token for image-generation provider
• APP_API_KEY_SECRET — secret for generating API keys / HMAC
• Optional third-party keys (OpenAI, Cloud storage, etc.)

• POST /api/images/generate 🖼️

  • Request: { prompt: string, base64_img?: string }
  • Response: { url: string }
  • Protected by API key guard (Header: x-api-key)

• POST /api/api-keys 🔐

  • Create/manage API keys for clients (admin-only)

• Auth/usage endpoints

  • Basic examples in src/auth and src/api-key modules

Project structure (recommended, simplified)

• src/
  • main.ts — bootstrap
  • app.module.ts — root module aggregation
  • app.controller.ts / app.service.ts — example
  • api-key/
    • api-key.module.ts
    • api-key.controller.ts
    • api-key.service.ts
    • dto/
  • auth/
    • auth.module.ts
    • guards/ (ApiKeyGuard, RolesGuard)
    • strategies/
  • db/
    • prisma.service.ts — Prisma client provider
    • migrations/
  • image-generation/
    • image-generation.module.ts
    • image-generation.controller.ts
    • image-generation.service.ts
    • dto/
  • utils/
    • logger, helpers, validators
• prisma/
  • schema.prisma
  • migrations/
• test/
  • app.e2e-spec.ts
• package.json, pnpm-lock.yaml
• .env.example
• README.md

Prisma & Data Model (overview)

• prisma/schema.prisma includes models like:
  • User (optional)
  • Account / Organization (optional)
  • ApiKey { id, keyHash, name, enabled, createdAt, lastUsedAt, ownerId }
  • Usage / Audit records for tracking request counts

Testing

• Unit tests with Jest (src/**/*.spec.ts)
• e2e tests in test/ using supertest against a test instance
• Coverage: pnpm run test:cov

Common issues & troubleshooting

• "Property 'url' does not exist on type 'object'": some provider SDKs return unknown-shaped objects — see image generation service guard code (src/image-generation/image-generation.service.ts) that safely narrows the response before reading .url
• Verify REPLICATE_API_TOKEN and provider responses by logging the raw output during development
• If Prisma errors occur, run prisma generate and migrate dev