Subscription Manager

PostgreSQLPrismaNext.jsReactTypeScriptVercel

A full-stack SaaS-style subscription billing system with robust business rules and relational data modeling.

Why this project exists: I built this to explore how real-world subscription billing systems enforce business rules, relational constraints, and data integrity across customers, plans, subscriptions, and invoices.

Focus: Backend API design and data modeling · Business rule enforcement for billing workflows · Admin-focused UX with validation-driven forms

Live Demo GitHub

Highlights

Full CRUD support for customers, plans, subscriptions, and invoices across 21 RESTful endpoints
Relational data modeling with Prisma, including cascading relationships and computed counts
Business rule enforcement for billing workflows (cancellation modes, invoice validation, deletion constraints)
Admin dashboard UI with validation-driven forms, confirmation dialogs, and error handling

Notable challenges

Designing relational schemas that enforce billing constraints and prevent destructive cascades
Implementing subscription cancellation modes while preserving historical invoice integrity
Preventing invalid invoice states through layered validation and business rules

Screenshots

Click any image to view full size

Subscription Manager plans list showing plan pricing, billing intervals, status, and actions. — Admin interface for managing subscription plans and pricing.

Subscription detail view showing customer and plan relationships with recent invoices. — Subscription detail view demonstrating relational depth and workflow context.

Create invoice form showing line items, totals, and validation-driven inputs. — Invoice creation flow with calculated totals and enforced validation rules.