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Sébastien BillionSB

Sébastien Billion

python / Flask / Django / vuejs #ReadytoHelp

€650/day
6 projects
Espenel, FR
8-15 years

Average response time: 1 hour

About Sébastien

Staff Backend Engineer — 12+ years delivering secure, scalable platforms.

I lead backend modernization and API strategy: Python (Flask/Django/FastAPI, aiohttp), event‑driven systems (Kafka), and search (Elasticsearch). I drive reliability at scale with Docker/Kubernetes, CI/CD (GitHub Actions/CircleCI/Travis), and cloud (GCP/AWS), backed by TDD/pytest and clear OpenAPI documentation. Proven in complex migrations (ES v1→v8, legacy to FastAPI), e‑signature integrations, and data consistency.

I operate as a technical owner: setting standards, mentoring, aligning architecture with product outcomes, and unblocking teams. Security‑first mindset (OSCP in progress). My focus: predictable delivery, observability, and resilient services that make user experiences faster and safer
  • Chinese

    Basic

  • German

    Conversational

  • English

    Fluent

  • French

    Native or bilingual

Can work on-site
Espenel (up to 50km), Grenoble (up to 10km), Valence (up to 10km), Lyon (up to 10km)

Experience

  • ANTICAFÉ & CO
    Malt logoOn Malt
    Faire un audit de l'application pour identifier les problématiques majeures dans le code
    October 2021 - October 2021
    Audit de l'application pour trouver l'origine des bugs majeures.
    Exploration du code / prise en main des outils externes et dépendances du projets / paramétrages
    Python HTML5 Django PostgreSQL
  • UKG
    Lead software engineer
    HUMAN RESOURCES
    April 2020 - November 2024 (4 years and 7 months)
    As a software engineer at UKG, my work was to enhance the integration of signature providers (Docusign, Adobesign and Protect and sign) inside the HR application named Document Manager. I had multiple goals to achieve and projets to work on.

    - An asynchronous API Rest developed in python using the aiohttp framework over asyncio. Multiple scopes were managed to limit the usage depending of the jwt token. The tests were writed using pytest and the documentation rendered with swagger using OpenAPI
    - A part of the legacy Django application, the esignature part. We had some new features to implement, bugs to fix, security to monitor and enhance, task and other slow query to improve, ElasticSearch migration from 1 to 8, etc...
    - We worked for a while on a FastAPI version of the API but the priority changed so it stayed a POC. It was really nice to user this framework where everything is easy, clean and well documented to do a nice documented async API in python
    - A kotlin esignature API to be integrated in the massive UKG architecture using multiple internal framework.
    Our team used the SCRUM methodology to manage the projects. For every projects we were careful about good practice: PEP8, docstring, tests, CI, multiple environment to deploy before production.
    During my work there, we did a move from on premise to gcp cloud.
    Python FastAPI Google Cloud Platform (GCP) Kubernetes Django Rest Framework
  • Jaccede
    Développeur fullstack et DevOps
    CIVIC AND SOCIAL ORGANIZATIONS
    February 2015 - Today (11 years and 4 months)
    Paris, France
    L'ensemble de ma mission actuellement est de gérer les serveurs et services, de concevoir et faire évoluer une API REST développé avec le framework Python Flask, de travailler en collaboration avec des partenaires et des prestataires sur des projets utilisant l'API ainsi que deux collègues développeur en interne.
    Il y a aussi les évolutions constantes à apporter au site web en full Angular.js utilisant également l'API.
    L'optimisation du SEO fait également parti de mes préoccupations récurrentes.

    J'ai eu la chance de pouvoir revoir totalement l'architecture web qui était en place à mon arrivée et de réécrire from scratch l'API. Il en a découlé la migration des serveurs, la migration de données complexes, dupliquées et mal formées, vers une base de données repensée pour accueillir des données saines et plus flexibles. Le site web a pu être découplé du backend pour devenir un projet en full AngularJS consommant les données de l'API.

    Cette liste est non exhaustive et tout un ensemble de technologies et de services sont à mettre en place et à maintenir au quotidien.
    Python AngularJS Linux Amazon Web Services Nginx Apache Elasticsearch Kibana Android iOS SEO HTML5 CSS3 Bootstrap 3 API REST Responsive design Google Analytics Google Search Console Google AdWords GIthub Git

Reviews

5,0

Out of 4 ratings

JordanJ

Jordan

ANTICAFÉ & CO

Reviewed on 20/10/2021

So far so good avec Sébastien. Compréhensif et pro actif, on avance sereinement et nous sommes confiant ! Merci !
AdamA

Adam

ADCOME

Reviewed on 18/10/2018

Sébastien m'a vraiment aider à retravaillé un script et ce dans un timing très court je le recommande.

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Education

  • Master degree of science
    SUPINFO
    2012

Skill set

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