Scalability Guide

Enterprise scalability patterns for global deployment

Current Stack (February 2026)

Layer	Technology	Version
Frontend	Next.js (Azure Static Web Apps)	15.5.12
Backend	NestJS (Azure Container Apps)	11.x
Database	MongoDB Atlas	7.x
Storage	Azure Blob Storage	-
CDN	Azure Front Door (optional)	-
CI/CD	GitHub Actions, Node.js 22	-

Current Architecture

┌──────────────┐     ┌──────────────────┐     ┌──────────────┐
│   Frontend   │────▶│  Azure Container │────▶│   MongoDB    │
│  (Static)    │     │  Apps (Backend)  │     │   Atlas      │
└──────────────┘     └──────────────────┘     └──────────────┘
                              │
                     ┌────────┴────────┐
                     ▼                 ▼
              ┌────────────┐   ┌────────────────┐
              │ Azure Blob │   │   Azure CDN    │
              │  Storage   │   │   (Optional)   │
              └────────────┘   └────────────────┘

---

Horizontal Scaling

Container Apps Auto-scaling

Azure Container Apps supports automatic scaling:

az containerapp update \
  --name ctrl-audio-backend \
  --resource-group Sonnance-WebApp \
  --min-replicas 1 \
  --max-replicas 10 \
  --scale-rule-name http-rule \
  --scale-rule-type http \
  --scale-rule-http-concurrency 100

Scaling Triggers

Metric	Recommendation
HTTP Requests	Scale at 100 concurrent connections
Memory	Scale at 70% memory utilization
Queue Depth	For background jobs (future)

---

Database Optimization

MongoDB Indexes

Ensure indexes exist for common queries:

// Artist Space queries
db.artistspaces.createIndex({ owner: 1 });
db.artistspaces.createIndex({ "collaborators.user": 1 });

// Track queries
db.tracks.createIndex({ project: 1, isDeleted: 1 });
db.tracks.createIndex({ owner: 1, createdAt: -1 });

// Search optimization
db.artistspaces.createIndex({ name: "text" });
db.projects.createIndex({ name: "text" });
db.tracks.createIndex({ name: "text" });

Aggregation Pipeline Optimization

// Use $project early to reduce document size
const pipeline = [
  { $match: { owner: userId, isDeleted: false } },
  { $project: { name: 1, image: 1, updatedAt: 1 } }, // Early projection
  { $sort: { updatedAt: -1 } },
  { $limit: 50 }
];

---

CDN for Global Distribution

Azure CDN Setup

Run the setup script:

cd infrastructure
chmod +x setup-cdn.sh
./setup-cdn.sh

CDN Benefits

Metric	Without CDN	With CDN
Latency (EU)	50-100ms	10-20ms
Latency (US)	150-200ms	20-30ms
Bandwidth costs	$0.087/GB	$0.081/GB
Cache hit ratio	0%	85-95%

CDN URL Integration

// Environment variable
NEXT_PUBLIC_CDN_URL=https://sonnance-images.azureedge.net

// Replace storage URLs with CDN
const cdnUrl = imageUrl.replace(
  'sonnancewebappstorage00.blob.core.windows.net',
  process.env.CDN_HOSTNAME
);

---

Mobile App API Considerations

Pagination

Always use cursor-based pagination for mobile:

// Cursor-based (recommended)
GET /tracks?cursor=507f1f77bcf86cd799439011&limit=20

// Response
{
  items: [...],
  nextCursor: "507f1f77bcf86cd799439012",
  hasMore: true
}

Response Compression

Enable gzip compression:

import * as compression from 'compression';
app.use(compression());

Efficient Endpoints for Mobile

// ✅ Good - Single request with embedded data
GET /artist-space/:id/full
// Returns: space + projects + recent tracks

// ❌ Avoid - Multiple round trips
GET /artist-space/:id
GET /projects?spaceId=xxx
GET /tracks?projectId=xxx

Image Optimization for Mobile

Return appropriate image variants:

// Mobile clients request smaller images
GET /artist/:id?imageSize=thumbnail

// Responsive image URLs in responses
{
  image: {
    thumbnail: "https://cdn/.../thumb.webp",  // 150x150
    medium: "https://cdn/.../medium.webp",    // 600px
    original: "https://cdn/.../original.webp"
  }
}

---

Caching Strategy

API Response Caching

// Redis caching (recommended for future)
import { CacheModule } from '@nestjs/cache-manager';
import * as redisStore from 'cache-manager-redis-store';

CacheModule.register({
  store: redisStore,
  host: 'localhost',
  ttl: 300, // 5 minutes
});

Cache Invalidation

Invalidate on mutations:

@Injectable()
export class ArtistService {
  async update(id: string, dto: UpdateDto) {
    await this.cacheManager.del(`artist:${id}`);
    return this.repository.update(id, dto);
  }
}

---

Background Jobs

Current: @nestjs/schedule

// Trash cleanup runs periodically
@Cron('0 0 * * *') // Daily at midnight
async deleteOldItems() {
  // Delete items older than 30 days
}

Future: Dedicated Queue (BullMQ)

For heavy processing (audio transcoding, batch operations):

import { BullModule } from '@nestjs/bull';

@Module({
  imports: [
    BullModule.registerQueue({
      name: 'audio-processing',
    }),
  ],
})

---

Monitoring & Observability

Azure Application Insights

import * as appInsights from 'applicationinsights';

appInsights.setup(process.env.APPINSIGHTS_INSTRUMENTATIONKEY)
  .setAutoCollectRequests(true)
  .setAutoCollectDependencies(true)
  .start();

Health Checks

import { HealthModule, HealthCheckService } from '@nestjs/terminus';

@Controller('health')
export class HealthController {
  @Get()
  @HealthCheck()
  check() {
    return this.health.check([
      () => this.db.pingCheck('mongodb'),
      () => this.storage.pingCheck('azure-blob'),
    ]);
  }
}

---

Scaling Roadmap

Phase	Feature	Effort	Impact
1	Azure CDN	1 hour	High
2	MongoDB indexes	2 hours	High
3	Response compression	30 min	Medium
4	Application Insights	2 hours	Medium
5	Redis caching	1 day	High
6	BullMQ for jobs	2 days	Medium

---

Last Updated: February 2026