ROI Spectrum
The Problem
SEO agencies and website owners lacked an integrated, multi-tenant solution to track ROI, audit logs, service tracking, and automated subscription billing transparently.
Architecture & Topology
Multi-tenant database schema architecture using Node.js/Express backend, React.js frontend, and hybrid storage using PostgreSQL for relational billing data and MongoDB for audit logs.
Tenant -> API Gateway -> Dynamic Tenant Selector -> Tenant DB (PostgreSQL / MongoDB) Stripe -> Webhook Handler -> Redis Queue -> Billing Aggregator
Engineering Challenges
Ensuring absolute tenant isolation and transaction safety during payment processing, along with handling real-time webhook retries and subscription life cycles.
Applied Solutions
Implemented schema-level tenant filtering alongside a resilient Redis event bus to parse incoming Stripe webhooks asynchronously. Built custom middleware to dynamically set DB contexts based on tenant headers.
Results & Benchmarks
Successfully deployed and launched the platform at roispectrum.com, handling hundreds of active tenants, reducing query response times by 30% through composite indexing, and fully automating subscription operations.
API Routing Specifications
| Method | Path | Objective |
|---|---|---|
| POST | /api/v1/tenants | Create new tenant workspace |
| POST | /api/v1/billing/checkout | Generate Stripe session |
| GET | /api/v1/reports/roi | Retrieve aggregated metrics |
Performance Tuning
Optimized query execution paths through multi-column indexing on tenant_id + created_at. Added Redis caching for read-heavy tenant settings, improving API response times from 150ms to 40ms.
Lessons Learned
Decoupling the billing pipeline from the core API workflow using an event queue prevents database lockups during traffic spikes.
SaaS Multi-Tenant Database ERD
Analyze schemas, keys, and foreign relational bindings
Tenants Schema
Stores company workspaces & domains- id:Primary unique identifier
- subdomain:Subdomain routing identifier