Bold Stack

Bérenger Salmon · Bold Stack · Lead Backend & DevOps

Your backend, from API to production.

I design your APIs in TypeScript, ship them on Google Cloud and equip the team that keeps them moving. One point of contact, from the first architecture decision to production monitoring.

Let’s talk about your project See my work
  • 7 years of experience
  • Lyynk, Yaago, Masteos, Kaliop
  • 100% remote

01 / Expertise

What I do

Backend

APIs & data

I build Node.js and NestJS APIs in TypeScript, model data in PostgreSQL with Prisma and tune queries as load grows.

  • TypeScript
  • NestJS
  • PostgreSQL
  • Prisma

DevOps

Cloud & production

I design and run complete Google Cloud infrastructures, from Cloud Run to Kubernetes. I automate releases and set up monitoring for errors, performance and costs.

  • Cloud Run
  • Cloud SQL
  • Pub/Sub
  • Kubernetes
  • Docker
  • CI/CD
  • Grafana
  • Sentry

Lead

Architecture & team

I help the team settle architecture decisions, review code and coach developers so everyone can work on production with confidence.

  • Architecture
  • Code review
  • Mentoring

Plus · Applied AI

LLMs & chatbots

I integrate LLMs such as Gemini into your product with the same standards as the rest of the backend: security, GDPR compliance, usage monitoring and cost control.

  • Gemini
  • Vertex AI
  • LLM
  • RAG

02 / Work

Selected missions

Mental health · App for young people

Lyynk

Lead Backend & DevOps · Freelance

Since March 2024

Lyynk is a mental health app used by hundreds of thousands of young people. I’m the technical lead for backend and cloud: a NestJS, Prisma and PostgreSQL architecture, and the entire Google Cloud infrastructure behind the app, async processing, internal tools and product analytics.

I lead the backend team (architecture decisions, code reviews, coordination with product and frontend) and designed an LLM-powered chatbot with a focus on security, GDPR compliance, usage monitoring and cost tracking.

requests per day
~300,000
average response time
<100 ms
production deploys per day
1–2
  • NestJS
  • Prisma
  • PostgreSQL
  • Cloud Run
  • Cloud SQL
  • Pub/Sub
  • BigQuery
  • Gemini

DevOps mission · Freelance

Yaago

DevOps Engineer, GCP & Kubernetes January 2024

A short mission focused on running and evolving a Kubernetes infrastructure on Google Cloud: configuration, application deployments, platform reliability, plus a few fixes on the React Native app.

  • GCP
  • Kubernetes
  • React Native

Proptech · Real estate investment

Masteos

Full-Stack Developer Dec 2020 – Jan 2024

In a 15-developer tech team, I redesigned the backend architecture with NestJS and migrated the infrastructure from Heroku to Google Cloud Run with zero downtime. Also: full-stack features (React, React Native), test coverage and deployment reliability.

  • NestJS
  • TypeScript
  • MongoDB
  • Cloud Run
  • React Native
  • Jest

Event management · Full-time

Kaliop

Full-Stack Developer, Node.js / Vue.js Sep 2019 – Dec 2020

At Kaliop Interactive Media in Montpellier, on an event management application: building new features, estimating and challenging user stories with the client, and setting up end-to-end tests with Cypress.

  • Node.js
  • GraphQL
  • Apollo
  • Vue.js
  • Cypress

03 / Testimonials

In their words

Excerpts from LinkedIn recommendations, translated from French.

“Bérenger owned the entire backend and infrastructure at Lyynk […]. Architecture, GCP infrastructure, security, CI/CD, monitoring: he built a solid, high-performing platform that handles the load while allowing daily production releases. […] Bérenger was always exceptionally responsive, well beyond working hours: a production issue on an evening or a weekend, he was there and he fixed it. He committed to the project as if it were his own, with a level of involvement that’s rare for a technical profile.”

Ryan Baazia Product Director, Lyynk

“Over time, my role shifted from supervision to true collaboration, as Bérenger fully mastered the stack and became a driving force on complex topics. Together we carried out a complete re-architecture of the stack, with great synergy. […] I highly recommend him.”

Romain Freydiger Backend technical lead, Masteos

“Bérenger exceeded the expectations I had of a good developer. Always very dynamic and technically sharp, he’s the ideal person to drive any meeting and ship value!”

Adrien Barbier Former direct manager at Masteos, now Head of Engineering at Betclic

04 / Contact

Let’s talk.

I work as a freelancer, fully remote, with startups and scale-ups. Need to evolve your backend, take back control of your GCP infrastructure or ship an AI feature? Drop me a line.

Email me Connect on LinkedIn