Senior Full-stack Engineer

Ontologize; Paris; Hybride; EUR 95 000 - 125 000; Plein temps

Avantages offerts par ce poste

25 days of paid vacation

Employer-paid health coverage

Daily lunch provided

Full reimbursement of public transport costs

Résumé du poste

Ontologize is seeking a Senior Full-Stack Engineer in Paris. The role involves developing a unique learning portal using Python and Next.js, engaging directly with users, and mentoring junior engineers. Responsibilities include building high-quality code and utilizing AI tools to enhance software development. Base salary ranges from €95k to €125k, with benefits including paid vacation, healthcare coverage, and meal benefits. The position supports a hybrid work model, requiring 3 days a week in the office.

Qualifications

• B2 minimum English level for technical discussions.
• Strong experience in backend languages is essential.
• Comfort with AI tools as a core part of development.

Responsabilités

• Take ambiguous problems, deliver working software.
• Build and maintain APIs and data systems.
• Work across Python backend and Next.js frontend.

Connaissances

Strong experience in a backend language (Python, Java, Go)

Strong data modeling and API design skills

Competency with SQL

Familiarity with hexagonal architecture

Familiarity with React/Next.js

Curiosity about DevOps

Outils

PostgreSQL

AI coding tools

Description du poste

About Ontologize

At Ontologize, we teach people to become Forward Deployed Engineers. We are the sole training partner for Palantir Technologies. We have directly taught thousands of people across more than 250 Palantir customers and partners — and many tens of thousands more via our YouTube channel.

We find teaching very fulfilling, and are honored to be trusted by companies and governments across the Western world. Our users learn to build on Palantir’s software to accomplish things like building ships faster, improving healthcare in hospitals, adding resiliency to their supply chains, accelerating military targeting workflows, reducing the likelihood of forest fires, repatriating manufacturing to their home countries, combatting fraud, reallocating capital expenditures, reducing errors in medical equipment, and much more. Teaching people to build with AI is a substantial part of our work.

We do not do any Palantir implementation work — only training and enablement — which makes us unique in the broader Palantir ecosystem.

Ontologize is profitable, growing fast and we have not taken VC funding.

Company Values

• Integrity: Above all else, value your integrity. Do not lie. Take responsibility for your mistakes.
• Respect: Respect yourself, your colleagues, and our customers. Earn the respect of those around you. Respect is hardest, and therefore most vital, in moments of conflict and disagreement.
• Initiative: Act without waiting to be told to do so. Seek to understand what the team must accomplish and take responsibility for contributing to the best of your ability.
• Production: Create a body of work. Writing, coding, recording, building, sketching — anything that gives form to your creativity.

About the Role

We're looking for a senior full‑stack engineer who can own problems and opportunities end‑to‑end.

From databases to APIs to GUIs, you ship high‑quality code without sacrificing speed. You'll work across our Python backend and Next.js frontend, building our learning portal and live training infrastructure. This entails not just writing code, but also using and building AI coding tools to improve the speed and quality of our work. Additionally, you will build AI‑powered features that help our users learn faster and more effectively.

Our learning portal is unique in that it will need to be deployable into restricted environments (e.g. classified NATO, UK, and US environments). You do not need a clearance for this role, though being open to going through the process of obtaining one in the future will be viewed as a nice‑to‑have.

This is an individual contributor role. You won't have management responsibilities, but we expect you to level up other engineers through mentorship and by modeling good practices.

This role will be our second hire in Paris. We are in the process of getting an office and anticipate making Paris our European hub for both software engineering and other roles.

This role does not require any experience with Palantir’s software.

Location

Paris, France (3 day/week in‑office)

Travel

We do once‑annual company colocations in the US (usually three days + travel). The engineering team does an additional colocation, probably in Paris for the foreseeable future.

What You'll Do

• Take ambiguous problems, decompose them, and deliver working software with minimal hand‑holding
• Build and maintain strongly typed APIs and well‑modeled data systems
• Work across the stack: Python backend, Next.js frontend, PostgreSQL, and our deployment infrastructure
• Use AI tools daily to accelerate development, learn the codebase, and ship faster
• Engage directly with end users and stakeholders to understand what actually needs to be built
• Contribute to our DevOps practices and bring ideas for better tools and processes

What We're Looking For

Technical Skills

• Strong experience in a backend language (e.g., Python, Java, Go, etc.). If you're coming from Java or Go and haven't done much Python, that's fine. We've found engineers from strongly typed backgrounds (including languages such as TypeScript) often adapt quickly to our conventions.
• Strong data modeling and API design skills.
• Competency with SQL — you can verify state in a production database and unblock yourself.
• Familiarity with hexagonal/ports‑and‑adapters architecture, or demonstrated ability to adopt architectural patterns quickly.
• Familiarity with modern frontend development. React/Next.js, performance optimization (useMemo, useCallback), error boundaries, and thoughtful component design.
• Curiosity about DevOps. You don't need to be an expert, but you should want to understand how your code runs in production.

AI‑Native Development

This is non‑negotiable. You should be using AI tools (Claude Code, Cursor, Codex, Windsurf, Amp, Opencode, etc.) as a core part of how you write software, not as a novelty. We use AI to interrogate our codebase, scope work, draft code, and accelerate every phase of development.

Our engineers get as many tokens as they need.

Language

Required English level: B2 minimum (CEFR) – must be comfortable participating in technical discussions and writing documentation in English.

How You Work

• You ship. You hold high standards and move quickly. These aren't in tension for you.
• You think about the second muscle: not just writing code, but improving the process of building software. You notice friction and fix it.
• You do low‑regret work. You ask the right questions upfront: What are the landmines? Is someone already working on this? What would it take for this to get merged?
• You thrive in ambiguity. We have some process, but not much. You're comfortable making progress without every detail nailed down.
• You communicate well with engineers (collecting context, respecting existing opinions) and with end users (understanding their actual problems).

Nice to Have

• Experience with feature flags and A/B testing infrastructure
• AWS experience
• Familiarity with Shape Up
• If you are familiar with Palantir’s software, that will neither help nor harm your application. But if you have deep expertise with Palantir’s software, especially with the APIs, that would be nice to have.

What We're Not Looking For

• Engineers who optimize for perfect over shipped.
• People who need extensive process and can't function without complete clarity on every detail.
• Developers who aren't using AI tools regularly in their workflow.
• Engineers from codebases without quality standards who will resist our conventions.

Compensation

• Base salary of €95k - €125k depending on experience
• Equity commensurate with a Series A start‑up
• Annual bonus — determined by a combination of company & individual performance

Time Off

• 25 days of paid vacation per year + applicable public holidays.
• Additional RTT days where applicable based on work schedule and agreements.
• Generous company discretionary days to support work‑life balance.

Benefits: Healthcare & Social Protection

• Employer‑paid complementaire santé (mutuelle) covering supplemental health costs (hospital, specialist, dental, optical), with 100% of the employee premium covered by Ontologize.
• Inclusive prévoyance (disability/death) coverage through Rippling EOR.

Retirement & Savings

• You participate in France’s mandatory pension system via payroll contributions.
• Ontologize offers access to optional company savings and retirement vehicles when available through Rippling.

Meal Benefits

• Daily lunch provided or meal vouchers covering the full cost of lunch on working days (meal vouchers are issued in compliance with tax‑advantaged titres‑restaurant rules).

Commuting & Mobility

• Full reimbursement of public transport costs for commuting to work (above the mandatory 50% minimum).
• Sustainable mobility allowance up to €900/year to support eco‑friendly commuting (bikes, carpooling, scooter, etc.) fully exempt from social charges within legal limits.

Remote Work & Home Office

• Home office support including equipment budget and a payroll‑paid remote work allowance to cover internet/electricity costs.

Family & Life Support

• Support aligned with French statutory parental leaves and additional company‑level family support programs where applicable (e.g. bereavement leave).