rdesousa.fr

About

I'm Roberto De Sousa, a developer with 10+ years of experience. I've navigated through dev roles (back/front), SRE/devops/architecture, all the way to lead/CTO. A very, very big fan of functional programming languages — but language-agnostic in practice.

My go-to stack:

  • Programming language: Elixir/Typescript/Python
  • Back: Phoenix
  • API: FastAPI
  • Front: Phoenix, Next.js
  • DB: Postgres, Typesense, Meilisearch, DuckDB
  • AI: Claude Code

In 2019, I realized that Agile management wasn't at all what it claimed to be. I worked with Vincent Cornet on a thesis critiquing Agile, which sparked my interest in the sociology of work and alternative organizational models. I've written articles and implemented alternatives such as Shape Up, game days, and many other things.

Since 2023, I've been entrepreneuring — co-founding cohortes, an AI-powered solution for collecting and analyzing employee testimonials in free text to help actors improving workplace conditions. I'm lucky to be part of l'Agora DODES and close to the ESS and QVCT movements.

I've reached the end of what we set out to do, so I'm looking for a new adventure — on a permanent contract, either as a hands-on CTO at an early-stage company with < 50 people, or as Head of Engineering / Staff Senior Engineer.

💡 What drives me: building a healthy, ambitious engineering culture.

  • 🙅‍♂️ No rush culture.
  • 🙅‍♂️ Finance, insurance, banking sectors don't interest me.
  • 🙅‍♂️ No micromanagement culture.
  • 🙅‍♂️ No industrial approach where devs churn through tickets without breathing.
  • 🚀 Project-based approach rather than ticket-based.
  • 🚀 Real space for research and learning.
  • 🚀 Empowerment over surveillance.
  • 🔧 Set a solid technical vision, capable of guiding long-term product decisions.
  • 🔧 Grow teams toward autonomy, quality, and technical curiosity.
  • 🔧 Work hand-in-hand with product AND sales to ship fast AND well.
  • 🔥 ESS, SCOP big plus.
  • 🔥 Shape Up.
  • 👎 Is live coding really a relevant method in the recruitment process?

dessroberto [at] gmail [dot] com

Experience

Since November 2023 — Co-founder & CTO (Cohortes)

An AI-powered solution for collecting and analyzing employee testimonials in free text to help actors improving workplace conditions. Incubated at Paris&Co and Willa.

  • Product & strategy
    • Facilitated scoping workshops with early users (unions, occupational psychologists, QVCT consultants)
    • Defined product and technical roadmap
  • Strategic partnership development
    • Co-authored and secured public funding (BPI grants)
    • Pitches and presentations with public bodies and incubators
    • Vibe coding/Copilot to rapidly develop client-facing demo MVPs, improving prospect → client conversion
  • Prospecting automation via AI MVP
    • Hubspot → AI agent for managing outreach (cold email, follow-ups, objection handling)
    • A/B testing on approaches → 2× response rate
  • Full Elixir stack (Phoenix, LiveView): SaaS development
    • Postgres for user and testimonial management
    • Typesense for semantic search via embeddings, integrated with a RAG system for contextual, enriched answers
    • AI agent orchestration via Oban for automated LLM analysis (self-hosted & cloud)
    • Reduced manual analysis time by 90%, freeing time for testimonial interpretation
  • Training delivered to tech and non-tech profiles: prompting, vibe coding, AI agents

February 2022 to November 2023 — Lead Tech (Sapiologie)

LCA & social impact ERP for SMEs

  • Foundational experience that gave me the entrepreneurial bug
    • Product co-construction with founders
    • Regular meetings with clients
    • Implemented Shape Up: project cycle-based work organization, better prioritization and commitment
  • Tech lead
  • Full Elixir stack (Phoenix, LiveView): ERP development
    • Reduced LCA calculation time by 90%
    • Technical oversight, architecture decisions, infrastructure management
    • Defined and maintained quality standards
    • Implemented a Datomic-like layer on Postgres for real-time change history and revert management

June 2021 to February 2022 — Lead Infra (Arkhn)

Making hospital data interoperable

  • Infrastructure modernization
    • Deployment and management of on-premises infrastructure inside hospitals (4 hospitals, ~100 TB of data, ~20 services)
    • Scaleway, Ansible, Nomad
  • Rolled out best practices: TDD, CI/CD
  • Organized game days on deployment processes to improve resilience and train teams
  • Postgres optimization for datalake creation: large-scale database migrations (~100 TB)
    • Used DBT (CTE) to structure migrations
    • Multiple indexing strategies (including BRIN)
    • Reduced migration processing time by ~70%

May 2019 to October 2020 — Senior Developer (Pandascore)

Esports data/metadata provider

  • Technical lead on the API (Elixir/Phoenix/Cowboy/ETL)
    • Feature development
  • Bridge between dev, machine learning, and infra teams
    • Standardized data contracts between ML / Backend / API teams (~10 people) to reduce sync overhead and ease migrations
    • Migrated from Helm to Kustomize for better maintainability
    • Internal training on Kubernetes and CI/CD

Feb 2019 to May 2019 — SRE (Thales Digital Factory, Paris)

Building a Kubernetes as a Service platform for a ~100-person tech organization

  • Designed and deployed a custom Kubernetes distribution under Rancher
  • Developed Kubernetes controllers/operators in Golang and Elixir
  • Collaborated directly with the Rancher team to optimize integration
  • Internal transition Helm → Kustomize for more robust infra management
  • Technical management of a 7-person engineering team

Jul 2016 to January 2019 — SRE (Ritmx, Paris)

SRE within the infrastructure teams of ticketing distribution applications in Île-de-France

  • Led infrastructure modernization in a constrained environment
    • Deployed and managed one of the first bare-metal Kubernetes clusters in the public sector
    • Migrated internal environments (~20 services, ~20 Kubernetes servers) to Terraform/GCP/Kubernetes/Helm
    • Led CI/CD and log management: Fluent/Prometheus/Thanos
    • Developed custom Kubernetes controllers in Elixir
  • Spread DevOps practices across 5 teams, ~50 people
    • Led internal training: Git, Kubernetes, Ansible, Docker
    • Supported teams in Kubernetes adoption
  • Research and publication on a critique of Agile methods

March 2016 to Jul 2016 — Scala Developer (Keljob.com)

Job board application

  • Development in Scala with Play2

Apr 2015 to March 2016 — DevOps Consultant (Banque de France, Paris)

Banque de France – Big Data Division

  • Puppet referent within a dedicated ops team for Big Data & observability stacks
    • Developed Puppet modules to deploy and configure distributed services: Elasticsearch, MongoDB, Hadoop, Spark
    • Set up an automated testing platform for Puppet modules using Docker with Scala integration
    • Expert on the ELK stack: tuning, deployment, and infrastructure integration

Dec 2014 to Apr 2015 — Java Developer (VSCt, Paris)

Developer at Voyage-SNCF

  • Development:
    • Java 1.8, AngularJS
    • Evangelism on functional programming with Java 1.8

Apr 2013 to Nov 2014 — Java Developer / DevOps (Sopra, Paris)

Building https://mailiz.mssante.fr/, a secure messaging platform for healthcare professionals

  • Web platform development
    • Java backend with Liferay
    • Perl scripts for data processing and Elasticsearch integration
  • Infrastructure industrialization
    • Led automated deployment with Puppet, CI/CD
    • Configuration of nginx, MySQL, Jenkins, ELK
    • Reproducible dev environments via Vagrant
    • Load testing with JMeter (scenarios + analysis)

Education

2011–2013: Master's in Computer Science Engineering — Université Paris Diderot

2007–2011: Bachelor's in Computer Science — Université Paris Diderot