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Alex Ndungu

CTO + Software Engineer + ML Engineer

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Let's talk
HomeAboutExperienceProjectsSkillsContact

Alex Ndungu

Backend systems, machine learning retrieval, and clean product-minded engineering for teams that care about reliability.

GitHubLinkedInLeetCodealexmeta517@gmail.com
Multi-Tenant Real Estate Operating System

Harlem Manage

Built the full backend of a multi-tenant proptech platform: 46-tool role-based AI agents, real-time M-Pesa WebSocket payment flows, a 3-queue Celery task system, and a PII-scrubbing observability stack.

46

AI agent tools

4

RBAC user roles

3

Celery queue types

Problem statement

Property management in the target market is not just CRUD over properties and tenants. It requires organization-level isolation, financial correctness, payment reconciliation, operational coordination across multiple roles, and localized workflows that reflect how real rental systems run in Kenya.

Architecture breakdown

I framed the system as a distributed, multi-tenant SaaS platform with strict relational modeling, RBAC enforcement across the application and AI layer, M-PESA-first payment design, and Akoko as a first-class intelligence engine with role-specific execution modules, channel-aware outputs, and human escalation paths.

  • - Role-based AI agent system (GPT-4.1 Responses API) with dynamic tool selection across 4 roles and 46 tools — full audit trail per message for compliance
  • - M-Pesa C2B STK Push with OAuth2, field-level encrypted credentials (per organisation + property), and live payment status streamed via JWT-authenticated WebSocket consumers over Redis
  • - 3-queue Celery architecture over RabbitMQ (notification / scheduled / background) with 5 Beat tasks: monthly ledger generation, maintenance automation, payment reminders
  • - Production observability: structured JSON logging, per-request UUID tracing, recursive PII scrubber redacting 20+ sensitive field patterns before Sentry/GlitchTip transmission
  • - 2-level multi-tenancy (Organisation → Property) with fully isolated payment flows, RBAC enforcement, and field-level encryption transparent at ORM level

Tech stack explanation

Next.jsDjangoDjango REST FrameworkPostgreSQLM-PESAWhatsApp/SMSAkoko AI

System diagram

[ Organizations ]
      |
      v
[ Multi-Tenant Core ] ---> [ Properties / Units / Tenants ]
      |                             |
      |                             +--> [ Lease & Rent Engine ]
      |                             +--> [ Ledgers / Reconciliation ]
      |
      +--> [ RBAC Layer ]
      |        +--> Owner
      |        +--> Manager
      |        +--> Caretaker
      |        +--> Tenant
      |        +--> Guard
      |
      +--> [ Akoko Intelligence Layer ]
               +--> Owner Execution
               +--> Caretaker Execution
               +--> Tenant Execution
               +--> Guard Execution

Key challenges

Harlem Manage is a Kenya-first, multi-tenant real estate operating system built for landlords, agencies, and property firms. It combines property workflows, tenant and lease management, financial reconciliation, communication channels, and Akoko, a deployed operational intelligence layer that adapts by role.

  • - Positioned the product as a real estate operating system for African rental infrastructure, not a simple management panel.
  • - Integrated operational intelligence directly into the product through Akoko rather than treating AI as a future add-on.
  • - Created a strong systems case study spanning SaaS architecture, fintech workflows, and access-controlled AI behavior.

What I learned

AI becomes much more valuable when it is embedded inside operational workflows rather than exposed as a generic assistant.
Multi-tenant architecture needs to be treated as a system-wide discipline across schema design, service logic, and permissions.
Local market context like M-PESA, language behavior, and escalation norms can meaningfully shape architecture decisions.