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Yassir Halaoui
FR
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Paris · France · Remote

Senior Java and React developer in Paris

Nine years of Java and React in places where a bug costs real money: two banks, a payments group, an insurance platform. I take missions on-site in Paris and Île-de-France, or remote from anywhere in France.

In short

Yassir Halaoui is a senior fullstack Java and React developer based in Paris. He has nine years of experience in banking, payments and insurance, and currently works with Java 21, Spring Boot 3.5, Kafka with Debezium, React 19 and Kubernetes on Azure. He takes missions on-site in Paris and Île-de-France and remotely across France.

Java and React in production
9 years
Employers and consulting missions
5
Current stack, in production
Java 21 · React 19

How I work

Where I work

I live and work in Paris. Missions can be on-site, hybrid or fully remote. Hybrid is the usual arrangement, two or three days a week at the client.

On-site I cover Paris (75) and all of Île-de-France: Hauts-de-Seine (92) including La Défense, Seine-Saint-Denis (93), Val-de-Marne (94), Yvelines (78), Essonne (91), Val-d'Oise (95) and Seine-et-Marne (77). Remote, anywhere in France, with a trip in for the workshops that matter.

What I'm usually brought in for

The work sits where two systems meet: a card processor and a mobile app, a database and a Kafka topic, a SOAP partner and a modern Spring service. That's where integration bugs, retry storms and audit gaps live, and it's the part I like most.

I write both ends. On my current mission that means Java 21 services behind a React 19 micro-frontend, shipped from Azure DevOps to Kubernetes, with the tests, the security scan and the quality gate in the same pipeline.

Sectors

Banking at CIH Bank and Société Générale. Payment cards at Pluxee. Insurance data exchange at Docaposte. An automotive rental platform through a consulting firm. Every one of them regulated, audited, or both.

How we start

  1. 01

    Send the dates, the stack and the number of on-site days.

  2. 02

    A twenty-minute call about the team and the system.

  3. 03

    A written quote and a start date.

Write to me · consultingyassir@gmail.com

Stack

Backend
  • Java 21
  • Spring Boot 3.5
  • Spring Batch
  • Kafka
  • Debezium
Frontend
  • React 19
  • Next.js
  • TypeScript
  • Module Federation
Data
  • PostgreSQL
  • Oracle
  • Redis
  • Elasticsearch
Platform
  • Azure AKS
  • Kubernetes
  • Terraform
  • Azure DevOps

Questions

Are you available for a freelance Java React mission in Paris?

Write to me with the dates, the stack and how many days on-site you need, and I'll tell you straight away whether it fits. I've worked through consulting firms and I'm on Malt.

Do you work remotely across France?

Yes. Remote works well for most backend and frontend work. On a long mission I like to be on-site for the first weeks, because that's the fastest way to learn the people and the system.

What is your daily rate?

It depends on the length of the mission, the number of on-site days and the scope. I quote in writing after a short call.

Which Java and Spring versions have you used in production?

Java 8, 11, 17 and 21, and Spring Boot up to 3.5. I've done the migrations between them as well, including moving batch jobs onto Spring Boot and replacing hand-written JDBC with Spring Data JPA.

Are you a backend developer or fullstack?

Fullstack. I ship React from version 17 to 19, Next.js, TypeScript and micro-frontends with Module Federation, and most of my missions have covered both ends.

Have you worked in regulated environments?

All of my missions have been regulated: bank transfer products, digital signature for banking documents, payment card PIN security, insurance data exchange. Secure-by-design reviews, audit trails and mutual TLS are normal working conditions for me.

Shipped work

Competences behind it

Field notes

Also on offer

Every competence