Architecting Bulletproof Systems for Three Decades.

Highly accomplished Senior Systems Engineer with nearly 30 years of professional experience architecting, scaling, and maintaining mission-critical enterprise applications. Technical specialist in modern C# and core .NET ecosystems (.NET 6/8/9), focusing heavily on robust backend architecture, secure RESTful API integrations, and complex database performance optimization.

mailforlester@gmail.com

+27 079 802 2161

Core Infrastructure

Technical Architecture & Stack

Core Backend & APIs

Modern .NET Core, .NET 6/8/9, C#, ASP.NET Core, RESTful/Minimal APIs, WCF Services, and clean Service-Oriented Architecture (SOA).

Database & Integrations

Advanced SQL Server T-SQL optimization, stored procedures, PostgreSQL implementation, Entity Framework Core, and data extraction pipelines.

DevOps & Lifecycle

Azure DevOps CI/CD pipeline structures, Git workflow management, Docker Containerization, and full visual workflows using Camunda BPMN.

Track Record

Highlighted Professional History

A comprehensive background managing production systems, resolving active architectural incidents, and converting complex enterprise business logic into clean, tested features.

Certifications

MCP: C#.NET MCP: COM+.NET Camunda BPMN

Senior Full Stack / Backend Integration Developer

R3Developers Ltd. Pty

Feb 2024 – Present

Engineered core Line of Business (LOB) backend infrastructure and critical automation layers using C#.
Charted and documented visual software paths using Camunda BPMN to ensure knowledge transfer.
Supervised data extraction pipelines handling multi-tier supplier APIs.

Senior Developer – Core Systems Integration

MMS Africa

Jan 2025 – Present

Fabricated secure backend and client-facing integration layers across multi-tier APIs using modern web structures.
Commanded codebase optimization initiatives, assuring platform stability.

Senior .NET Integration & Backend Developer

Tech2Cart

Key Delivery Project

Architected the core Line of Business (LOB) backend infrastructure and automated real-time inventory synchronization feeds.
Resolved critical backend incidents, optimized massive relational catalogs, and deployed long-term database bug fixes.

Legacy Enterprise Footprint

Hollard Insurance (2023–2024) Maintained core systems, handling real-time debugging and telemetry verification using DotNet Counters.

Standard Bank (2021–2022) Refactored core Fraud Management structures to .NET 6, deployed via automated Azure DevOps CI/CD loops.

Johannesburg Stock Exchange (2019) Contributed to Agile Scrum sprint tracks building high-reliability financial instrument applications.

Vodacom South Africa Upgraded critical legacy Payment Gateway subsystems to strict PCI TLS 1.3/3.1 compliance regulations.