Building financial infrastructure, intelligent systems, and products that solve real-world problems.

I’m a Senior Product Engineer focused on building production-grade systems across payments, financial infrastructure, backend architecture, and AI-powered applications.

My work spans the full product lifecycle — from understanding the business problem and designing the architecture to writing the APIs, integrating external providers, deploying the system, monitoring it, and making sure it continues working when things go wrong.

📍 Lusaka, Zambia

I build the infrastructure behind digital payments in African markets.

My experience includes mobile money integrations, payment gateways, merchant platforms, USSD systems, settlement infrastructure, wallets and reconciliation systems.

                         ┌─────────────────┐
                         │     Customer    │
                         └────────┬────────┘
                                  │
                                  ▼
                    ┌─────────────────────────┐
                    │    Mobile Money / USSD  │
                    └────────────┬────────────┘
                                 │
                                 ▼
                    ┌─────────────────────────┐
                    │     Payment Gateway     │
                    └────────────┬────────────┘
                                 │
                 ┌───────────────┼───────────────┐
                 ▼               ▼               ▼
            Collections      Wallets        Disbursements
                 │               │               │
                 └───────────────┼───────────────┘
                                 │
                                 ▼
                       ┌──────────────────┐
                       │    Settlement    │
                       └────────┬─────────┘
                                │
                                ▼
                       ┌──────────────────┐
                       │  Reconciliation  │
                       └──────────────────┘

• 📱 MTN MoMo
• 📱 Airtel Money
• 📱 Zamtel
• 🔗 Payment gateway integrations
• 💰 Collections & disbursements
• 🧾 Payment links
• 🔲 QR payments
• 💸 Bulk payouts
• ↩️ Refunds
• 🏦 Merchant wallets
• 🔐 KYC & merchant onboarding
• 🔄 Transaction reconciliation
• 📊 Financial reporting
• 📞 USSD gateway architecture

One of the areas I'm particularly interested in is cross-border financial infrastructure in Africa.

I've worked on settlement infrastructure for cross-border freight corridors in Southern Africa, exploring stablecoin rails to reduce the complexity and settlement time between currencies.

                    CORRIDOR A
                         │
                         ▼
                  ┌──────────────┐
                  │     Payer    │
                  └──────┬───────┘
                         │
                         ▼
               ┌────────────────────┐
               │  Settlement Switch │
               └─────────┬──────────┘
                         │
              ┌──────────┼──────────┐
              ▼          ▼          ▼
          Local FI   Stablecoin   FX / Liquidity
              │       Settlement       │
              │          │             │
              └──────────┼─────────────┘
                         │
                         ▼
                  ┌──────────────┐
                  │     Payee    │
                  └──────────────┘
                         │
                         ▼
                    CORRIDOR B

Faster settlement · Lower costs · Better reconciliation · Programmable infrastructure

I'm building toward a future where AI isn't just a chatbot sitting beside a product — it's part of the product's workflow.

I'm particularly interested in:

• 🧠 AI Agents
• 🔎 Retrieval-Augmented Generation
• 🛠️ Tool Calling
• 📄 Document Processing
• 🔄 Intelligent Workflows
• 🤖 Autonomous Business Processes
• 🧩 Multi-step Agents
• 🔐 Human-in-the-loop systems
• 📊 AI Observability

                         ┌───────────────┐
                         │     User      │
                         └───────┬───────┘
                                 │
                                 ▼
                       ┌──────────────────┐
                       │    AI Agent      │
                       └────────┬─────────┘
                                │
              ┌─────────────────┼──────────────────┐
              ▼                 ▼                  ▼
         Retrieve Data      Call Tools        Understand
              │                 │                Intent
              └─────────────────┼──────────────────┘
                                │
                                ▼
                       ┌──────────────────┐
                       │ Execute Workflow │
                       └────────┬─────────┘
                                │
                                ▼
                       ┌──────────────────┐
                       │ Validate Result  │
                       └────────┬─────────┘
                                │
                                ▼
                             Outcome

Backend engineering is at the core of my work.

I build systems around:

APIs · Microservices · Event-driven architecture · Distributed systems · Authentication · Authorization · Databases · Messaging · Integrations

I particularly enjoy designing systems where multiple services and external providers need to work together reliably.

Reliability
     ↓
Correctness
     ↓
Security
     ↓
Observability
     ↓
Scalability
     ↓
Performance

In payments, the happy path is easy.

The real engineering challenge is:

Request
   ↓
Timeout
   ↓
Retry
   ↓
Duplicate
   ↓
Provider Callback
   ↓
Partial Failure
   ↓
Reconciliation

That's why I favour:

• Explicit state machines
• Idempotency
• Transactional boundaries
• Durable messaging
• Transactional outbox patterns
• Callback replay handling
• Duplicate suppression
• Strong audit trails
• Observable workflows
• Reconciliation-first architecture

The system should always be able to answer:

What happened to this transaction, why did it happen, and where is the money now?

I've worked with security controls relevant to production payment infrastructure, including:

• PCI DSS v4.0
• ISO 27001 controls
• mTLS
• Secrets management
• Audit trails
• Role-based access control
• API security
• Authentication & authorization
• Transaction monitoring

I'm also familiar with the Zambian regulatory environment, including:

Bank of Zambia · ZICTA · Data Protection Act 2021

Public repositories will be linked here as they become available.

I believe documentation is part of engineering.

I document systems so that the architecture can be understood by:

• Engineers
• Product teams
• Operations teams
• Compliance teams
• Business stakeholders

Typical documentation includes:

• Architecture diagrams
• API contracts
• Sequence diagrams
• Database models
• Payment flows
• Failure scenarios
• Integration specifications
• Deployment procedures
• Reconciliation processes

I'm currently focused on building:

Payment gateways, wallets, collections, disbursements and reconciliation.

Infrastructure for faster and more programmable settlement across African markets.

AI agents, intelligent workflows and automation integrated into real products.

Products around accounting, collections, savings, communications and business automation.

I'm interested in working with teams building:

FinTech · Payments · AI · SaaS · African Financial Infrastructure · Developer Platforms · Automation

I'm open to:

• Senior Software Engineer roles
• Senior Product Engineer roles
• Backend Engineering
• Payments Engineering
• FinTech Engineering
• AI Engineering
• Platform Engineering
• Technical Leadership
• Architecture & System Design
• Product Engineering

If you're building something ambitious around payments, financial infrastructure, AI or software products, I'd be happy to connect.

Portfolio https://next-js-portifolio-nine.vercel.app/

GitHub https://github.com/mosesjust2016

Email mjjustme26@gmail.com