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Case study

EstateOS

Portfolio stress testing for real estate investors and advisors. Originally built as an internal tool, now being launched as a SaaS platform.

Full-Stack SaaS · Real Estate Technology · Launching Soon

  • 25+
    API Endpoints
  • 10
    Database Tables
  • 3
    Background Workers

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EstateOS portfolio dashboard
FIG. 01 — ESTATEOS. REAL ESTATE TECHNOLOGY, MULTI-TENANT SAAS.

01 —

Project Overview

EstateOS started as an internal tool built to stress test real estate portfolios against economic scenarios. After proving its value, it's now being developed into a full SaaS platform for investors and advisory firms.

The platform is architected as a monorepo with shared TypeScript packages, ensuring type safety from database queries through API responses to frontend components.

Key technical challenges included building a deterministic financial calculation engine, implementing background job processing for PDF generation, and designing a multi-tenant architecture with plan-based feature gating.

Technical Scope

  • Multi-tenant SaaS with tiered subscription plans
  • Background job processing with retry logic
  • PDF report generation with S3 storage
  • Stripe subscription billing with webhook handling
  • Token-based portfolio sharing system
  • White-label branding capabilities
  • Email notification system with preferences
  • CSV bulk import with row validation

02 —

Technology Stack

Built on a modern, type-safe foundation designed for reliability and maintainability.

  • Monorepo

    npm workspaces

    Shared packages and coordinated builds

  • Frontend

    React + Vite + TypeScript

    Type-safe UI with fast HMR

  • Backend

    Express.js + TypeScript

    RESTful API with strict typing

  • Database

    PostgreSQL + Drizzle ORM

    Type-safe queries and migrations

  • Queue System

    BullMQ + Redis

    Background job processing

  • Authentication

    Clerk

    OAuth and email auth flows

  • Payments

    Stripe

    Subscriptions and webhooks

  • Email

    Resend

    Transactional notifications

  • Storage

    AWS S3

    Secure document storage

03 —

Security Architecture

Defense-in-depth approach to protecting user data and platform integrity.

  • Route Protection Middleware

    All API endpoints protected with authentication verification before processing requests.

  • Plan-Based Feature Gating

    Subscription tier enforcement at the API level prevents unauthorized feature access.

  • Token-Based Sharing

    32-byte hex tokens with 30-day expiration for secure, revocable portfolio sharing.

  • Cascade Deletes

    Foreign key constraints ensure data integrity and prevent orphaned records.

  • Webhook Signature Verification

    Stripe webhook payloads verified before processing payment events.

  • Signed URLs

    S3 documents accessed via time-limited signed URLs (24hr expiry).

04 —

Architecture Highlights

  • Pure TypeScript Math Engine

    Zero-dependency calculation package (@estateos/math) for deterministic financial computations including PMT, DSCR, LTV, and Herfindahl index.

  • Background Job Processing

    BullMQ workers handle PDF generation, email delivery, and alert creation with exponential backoff retry logic.

  • Data Conventions

    Monetary values stored as cents (integers), percentages as basis points (800 = 8%), UUIDs for primary keys.

  • Webhook-Driven Billing

    Stripe webhooks handle checkout completion, subscription lifecycle, and payment events with idempotent processing.

05 —

Data Model

PostgreSQL schema designed for multi-tenant isolation and data integrity.

  • users
  • portfolios
  • properties
  • snapshots
  • alerts
  • branding
  • email_preferences
  • reports
  • shares
  • waitlist

Need a custom platform like this?

Whether you need a multi-tenant SaaS platform, secure financial application, or complex data processing system, let's discuss your requirements.