A digital payments company partnered with 18North to create a robust, multi-tenant Subscription Management Platform from the ground up. The platform was envisioned to support flexible subscription logic, dynamic pricing, partner integration, and country-wise configurations for fintech clients with global footprints. The goal was to shift from monolithic limitations to scalable microservices with modular lifecycle control.

The client operates in the digital payments space, serving institutions, merchants, and end-consumers. Its key offerings include cross-border remittance, payment gateway, and wallet platforms across 24 countries. With a fragmented and hard-coded subscription system, the organization struggled to scale or customize offerings per region, partner, or regulatory needs.

• No reusable component architecture for subscription lifecycle.

• High dependency on the in-house remittance platform for user authentication and SSO.

• Inflexible integration with external payment gateways and limited ability to isolate failures.

• Manual workarounds for top-ups, discounts, renewals, and notifications.

• The previous in-house microservices attempt had failed to deliver usable outcomes.

18North designed and developed a microservices-based SaaS platform with built-in flexibility and scalability:

• Dynamic Subscription Lifecycle: Built core flows including registration, plan selection, renewal, cancellations, and top-ups.

• SSO & Role-Based Access: API handshake with the remittance platform enabled seamless partner and tenant integration.

• Multi-tenant Enablement: Logical separation by organization, product, plan, customer, and user ensured tenant-level isolation and extensibility.

• Payment Gateway Integration: A dual-mode interface (B2B and S2S) managed encryption, failure capture, and fraud prevention using AES 64-bit protocols.

• Notification Engine: Custom email/SMS templates configured per partner and triggered via events.

Faster Market Launch: New subscription models rolled out in 6+ corridors within 3 months.

Operational Efficiency: Reduction in support queries and manual interventions through automated lifecycle transitions.

Robust Security: AES-based encrypted transactions, token validation, and hardened session flows.

High Availability: Core microservices scaled independently; user services run efficiently on lightweight infrastructure.

Client Confidence: The solution became a flagship reference platform, reversing the previous failure.

A. Functional Architecture

• Domain-Driven Design: Independent microservices mapped to entities like User, Plan, Top-Up, Coupon, and Notification.

• Client-Side UI Pattern: Angular-based front-end with lightweight presentation layer for responsiveness.

• Subscription Core: Services for managing plans, top-ups, renewals, cancellations, payments, and white labeling.

• Gateways & Brokers: Kong API Gateway with HTTP header-based CORS. RabbitMQ considered but REST preferred for simplicity.

• SSO & Credential Management: Services integrated with remittance platform for seamless partner login flows.

• Entities Layer: Templates for Plans, Top-ups, Coupons, and Notification dynamically instantiated per tenant.

B. Non-Functional Architecture

• DevOps Tooling: Recommendations made for Docker (Container), Jenkins (CI/CD), ELK (Logging), and Dropwizard/Prometheus (Metrics).

• Security: Bespoke session tokening using cookies; OAuth2 and Keycloak evaluated but not adopted.

• Rate Limiting & Tracing: Kong-based throttling and distributed tracing options (Zipkin, Google Dapper) considered.

• Scalability:
  • High-volume services (e.g., Payments, Subscription Lifecycle) horizontally and vertically scaled.

  • Low-volume services (e.g., User Service, Credential Mgmt) deployed on lightweight virtual servers.

• Fault Tolerance: Retry/circuit breaker logic embedded into gateway layer with clear failure routing and fallback paths.