Open to selected consulting engagements

Senior .NET Engineer & Tech Lead · Paris

Critical systems, built to survive the trading day.

10+ years designing, modernizing, and operating the platforms that power energy trading, capital markets, insurance, and payments.

.NET · Angular · AzureDistributed & real-time systemsParis, France
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Omar Trabelsi
Senior .NET Engineer · Tech Lead · Paris
Experience
  • ENGIE GEMS
  • Crédit Agricole CIB
  • Aon
  • Orange
  • S-Money · Natixis
At a glance
10+years building production software
.NET 6→10recent microservices modernization
3detailed case studies
4critical domains: trading, markets, insurance, payments
01

Three systems, three kinds of pressure.

Real-time pressure, regulatory constraints, and modernization without downtime: three environments that reflect the work I do.

01
ENGIE GEMS
03.2025 — present
  • Energy trading
  • Real-time
  • Senior .NET Engineer

Context

Real-time pricing, booking and market-data flows across integrated trading applications.

The systems serve desks across multiple time zones, where price consistency, availability and fast diagnostics matter as much as feature delivery.

Technical contribution

  • Evolved .NET services for pricing, booking and real-time distribution.
  • Migrated microservices from .NET 6 to .NET 10 with non-regression testing.
  • Modernized CI/CD and production diagnostics.
Impact

A modernized platform delivered without disrupting trading activity, with stronger operational autonomy.

  • .NET 10
  • Angular
  • SignalR
  • RabbitMQ
  • Azure
  • Splunk
Read case study →
02
Crédit Agricole CIB
01.2022 — 02.2025
  • Capital markets
  • Sales & Trading
  • Tech Lead

Context

Sales & trading workflows, regulatory documentation and integrations inside a Global Markets environment.

The scope combined application development, traceability, infrastructure migration and technical leadership.

Technical contribution

  • Designed .NET 8 REST APIs and Angular features.
  • Migrated infrastructure components to new Windows Server environments.
  • Code reviews, documentation and engineering support.
Impact

End-to-end technical ownership, from API design and delivery through operational handover.

  • .NET 8
  • Angular
  • NgRx
  • SQL Server
  • Kubernetes
  • Kibana
Read case study →
03
Aon
10.2019 — 12.2021
  • Insurance
  • Modernization
  • Full Stack .NET / Angular Engineer

Context

Modernizing a legacy health and benefits platform while keeping existing business obligations running in production.

The work combined Angular/.NET Core modernization, data access and progressive Azure migration.

Technical contribution

  • Rebuilt modules with Angular and .NET Core APIs.
  • Migrated an IIS-hosted portal to Azure.
  • Public API integrations, data extraction and SQL procedures through Dapper.
Impact

A controlled evolution from a legacy platform to a modern architecture hosted on Azure.

  • .NET Core
  • .NET Framework
  • Angular
  • Azure
  • Dapper
  • SQL Server
Read case study →
02

Where I add the most value.

Complex problems where architecture, production constraints, and business workflows must stay aligned.

01

Build business-critical .NET platforms

APIs, microservices, and distributed systems engineered around reliability, operability, and real production constraints.

Explore →
02

Modernize live systems safely

Move legacy .NET Framework systems to modern .NET with a controlled approach to compatibility, testing, and regression risk.

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03

Diagnose production and performance issues

API latency, SQL, observability, and distributed incidents: trace the real behavior of the system before choosing a fix.

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04

Cloud delivery and operations on Azure

App Service, CI/CD, Key Vault, containers, and cloud operations—used pragmatically to improve delivery and reliability.

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03

A focused stack for complex systems.

The technologies I rely on most to build, modernize, and operate enterprise systems.

Backend

  • C#
  • .NET / ASP.NET Core
  • Entity Framework
  • Dapper
  • REST APIs

Frontend

  • Angular
  • TypeScript
  • RxJS
  • NgRx
  • ag-Grid

Cloud & platform

  • Microsoft Azure
  • Docker
  • Kubernetes
  • GitHub / Azure DevOps
  • CI/CD

Architecture

  • Distributed systems
  • Event-driven
  • Microservices
  • Real-time
  • Observability

Additional experience: RabbitMQ, Redis, SignalR, WCF, NHibernate, Argo CD, Splunk, Kibana, SonarQube.

For deeper Angular experience: Explore Angular expertise →

04

10+ years building software on the business-critical path.

  • 012025 — present
    ENGIE GEMS — Senior .NET Engineer
    Energy trading · pricing, booking, real-time market data
  • 022022 — 2025
    Crédit Agricole CIB — Tech Lead
    Capital markets · sales & trading workflows
  • 032019 — 2021
    Aon — Full Stack .NET / Angular Engineer
    Insurance · modernization and Azure migration
Earlier experience
  • 042018 — 2019
    Orange — .NET Developer
    Telecom · business workflows and SQL optimization
  • 052017 — 2018
    S-Money · Natixis — .NET Developer
    Payments · marketplace APIs, KYC, refunds
  • 062016 — 2017
    CNAM — .NET Consultant
    Public sector · project portfolio portal
  • 072015 — 2016
    Mi-Case Upstream — .NET Consultant
    Oil & gas
05

About

The hardest part is rarely writing the feature. It is understanding why a system produces the wrong result under real operating conditions.

I work on business-critical systems where reliability, performance, and maintainability matter more than novelty. My role often sits at the intersection of modern .NET architecture, production constraints, and complex business workflows.

I document systems, support teams, and take ownership of the less visible but decisive work: migrations, regression control, performance, observability, and incident analysis.

Based in Paris. Native in French and Arabic, fluent in English.

Read engineering notes →
06

Education & professional development

Education

  • 2015
    Engineering Degree in Computer Science
    Faculté des sciences de Tunis
  • 2012
    Preparatory Program in Engineering Sciences
    IPEI Monastir

Professional development

  • Cloud Computing Foundations
  • Advanced Azure & Cloud Architecture
  • Microsoft AI Skill Fest

Languages

  • French — native
  • Arabic — native
  • English — fluent
07

Working on a complex .NET system?

Architecture, modernization, performance, cloud migration, or production reliability—let’s start with the actual problem.

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