Node.js SaaS Backend Development

We build your SaaS backend on NestJS for enterprise-grade modularity with dependency injection, decorators, and a clear module/controller/service architecture — or on Fastify when raw throughput is the priority with its schema-based validation and plugin system that processes 75K+ requests per second. Both frameworks are TypeScript-native, support OpenAPI documentation generation, and provide clean patterns for middleware, guards, interceptors, and exception filters.

Background processing runs on BullMQ with Redis-backed queues for email sending, report generation, data imports, webhook deliveries, and billing reconciliation. Jobs support priority levels, delayed execution, rate limiting, retry strategies with exponential backoff, and dead letter queues for failed jobs. We build a queue dashboard for monitoring job status, throughput, and failure rates in real time — essential for any SaaS that processes asynchronous workloads.

Real-time features run on Socket.io with Redis adapter for horizontal scaling across multiple Node.js instances. We implement room-based broadcasting for tenant-scoped events, presence detection for online/offline status, and namespace separation for different feature areas. Use cases include live notifications, collaborative editing, real-time dashboards, chat, and activity feeds — all with automatic reconnection, message buffering, and delivery guarantees.

Database access is type-safe and migration-managed with either Prisma for its declarative schema, auto-generated client, and developer-friendly query API, or TypeORM for its decorator-based entity definitions and support for advanced patterns like table inheritance and custom repositories. Both integrate with PostgreSQL, MySQL, and SQLite. We implement query optimization, connection pooling, read replicas, and tenant-scoped data access at the ORM level.

For SaaS products that need independent scaling, we decompose the backend into microservices communicating via message brokers (RabbitMQ, Redis Streams, or NATS). NestJS microservices module provides transport-agnostic patterns for request-response and event-based communication. Each service owns its database, deploys independently, and scales horizontally based on its specific load profile — keeping your billing service isolated from your analytics service.

We architect your backend around domain events that decouple business logic from side effects. When a user upgrades their plan, the billing service emits a PlanUpgraded event that triggers entitlement updates, sends a confirmation email, records an audit entry, and notifies the analytics pipeline — all without the billing service knowing about any of these downstream consumers. This pattern makes your codebase extensible and your features independently testable.