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Founding software engineer @Revolty Hexa
Startup studio launching companies in AI, fintech, health, and web3.
Permanent
Paris
A few days home
Salary: Not specified
> 3 years
Skills we're looking for
FastAPI
React
Ubuntu
TypeScript
Crew
+4
You'll be part of
Incubator / Accelerator
Corporate Support
Average age: 34
60%
40%
Founded in 2011 as eFounders, Hexa is a startup studio that has launched over 40 companies with a combined valuation of over $4.5bn, including Aircall, Spendesk, Front, Swan, Yousign, and Upflow.
Today, our focus is on launching companies in the areas of AI, future of work, health, fintech, and web3 - with even more verticals to come. By 2030, our goal is to launch 30 startups a year.
Our unique model allows us to build companies from scratch in collaboration with exceptional founders, bringing them on board for 12 months while building the company together, from product to fundraising.
How do we do it? We provide entrepreneurs with:
- Foolproof startup ideas to beat the odds
- A team to build a best-in-class MVP
- A methodology to bring their product to market faster
- A brand to attract top talents
- Capital to fund the first 12-18 months of their startup’s life
- A community of fellow entrepreneurs & peers for life
Our approach creates exceptional companies: for us, that means startups that are fueled by ambition, and driven by purpose.
You'll be working on
Revolty is the solar battery that has already lived a first life.
Revolty gives lithium batteries a second life. They store the solar energy of the 1 million homes already equipped with solar panels. Smaller bills, smaller footprint. Our dream? Make the circular battery the energy heart of every home.
Revolty since the beginning :
Founded in July 2024, straight out of school by Valentin et Mathilde.
€2M of battery orders secured with 15 partner solar installers
3 battery prototypes deployed in real-life conditions
1M€ raised in January 2026 to bring our battery to market
First product on sale in 2027 !
Meet the Revolteam :
We’re a small, fast-growing team of six : two cofounders, a business crew, and three hardware engineers led by our CTO, Romain, with 8 years in battery startups and scaleups. Software? Nobody yet — and that’s the whole point: you’d be the first, with the entire software side of Revolty left to build.
We’re looking for a full-stack engineer to build the software brain of our battery fleet. Not one battery: hundreds of them in homes, all to be monitored, updated and piloted remotely. You get carte blanche on the architecture and the big technical choices. Together, we’ll go from our live POC to the first units on the market in 2027.
Your missions
Design the fleet architecture. The most structuring decision of the role, and it’s yours, with a clean slate to start from: multitenant model, real time (~10 s) vs. telemetry (1 Hz), message broker.
Operate the fleet, and set the standards for it. Provisioning, device identity, OTA updates without bricking a battery in someone’s basement, plus the monitoring, alerting and remote diagnostics you’ll set up from scratch.
Build the apps & turn data into decisions, from a blank page. One platform, three views (Revolty, installers, customers): live monitoring, control, alerts, plus the algorithms arbitrating energy flows.
Connect everything: home equipment through their own protocols (inverters, EV chargers, heat pumps), and the secure API you’ll design so flexibility operators and grid managers can pilot the batteries remotely.
We're looking for
The profile we’d love to meet
You have 3+ years of experience. Enough to have shipped things, broken a few, and learned from both.
You’ve built and run a fleet of connected devices… or you’re dying to. Provisioning, secure connectivity, OTA, monitoring, remote debugging, on an architecture you designed to scale: access management, encryption, CI/CD, resilience.
You’re a full-stack developer: front, back, databases, cloud. Bonus points if IoT protocols speak to you (Modbus, MQTT, HTTP, API…).
Bonus: data and product feel. Simulating energy histories, or simply caring about who’s on the other side of the screen, a homeowner, an installer. And the hardware behind it.
Our current prototype stack (nothing set in stone…come challenge it!). Frontend: Vite (React + TypeScript). Backend: Python / FastAPI. Databases: PostgreSQL + TimescaleDB. Cloud: Ubuntu servers. Device protocols: Modbus, MQTT, HTTP…
How we hire
The practical stuff
Permanent contract (CDI) with a €55 to 65k gross annual salary, plus BSPCE.
Offices in Paris (6th) and workshop in Montreuil. Remote work allowed (1 to 2 days per week).
Process: 3 interviews. An intro call (30 min), a technical one (1h) and a manager one (1h).
Just email our HR team (recrutement@revolty.fr) with your CV.
Key figures
In short
Average age
34
Gender
40%
60%
