Title: Senior Fullstack Software Engineer (Python / TypeScript / React)

Location: Paris (Morning Laffitte, Hybrid — 2 remote days/week)

Language requirement: French B2+ and English B1+

Contract: Full-time, CDI

About Symbiotic Security

Symbiotic Security is a cybersecurity startup based in Paris, building an AI-powered assistant that helps developers write secure code.

Integrated directly into IDEs and CI/CD pipelines, our solution detects and fixes vulnerabilities, including those generated by tools like GitHub Copilot.

We combine deep cybersecurity expertise, modern engineering practices, and cutting-edge AI to help developers build safer software, faster.

• Founded in 2024
• 21 team members across Paris and New York
• Strong engineering & product culture
• Modern offices at Morning Laffitte (Paris 9th)

We’re now expanding our tech team with a senior fullstack engineer who thrives in a collaborative and high-autonomy environment.

Role Overview

You will work on both backend (≈70%) and frontend (≈30%), contributing to our SaaS platform and internal tools. You will collaborate closely with:

• Abir — Engineering Manager
• Minh Thang — Tech Lead
• Édouard — CTO

This role has significant ownership, technical depth, and the opportunity to shape a fast-growing product from early stages.

Your Responsibilities

• Develop and maintain backend services and APIs (Python, Django).
• Build and improve frontend features (React, TypeScript).
• Contribute to our hexagonal architecture and DDD approach.
• Work on diverse topics: REST APIs, CLI tools, AI agents, monitoring.
• Improve performance, reliability, and code quality.
• Lead code reviews, testing strategies, and release processes.
• Mentor teammates and contribute to engineering best practices.
• Collaborate with product, design, and cybersecurity teams.

What We’re Looking For

Required

• 5+ years of professional experience in software engineering
• Strong experience with Python (Django = strong plus)
• Strong experience with React / TypeScript
• Solid SQL knowledge (PostgreSQL preferred)
• Experience working in high-quality engineering environments
• Ability to work and communicate in English (B2+) and French (B2+)
• Comfortable using LLMs (ChatGPT, Copilot, Claude)

Nice-to-Haves

• Experience with DDD or hexagonal architecture
• Experience with monitoring / logging / performance work
• Interest in cybersecurity (not required)

Mindset

• Curious and rigorous
• Autonomous and impact-driven
• Low ego, collaborative, strong communicator
• Product-oriented, eager to build meaningful software

Tech Stack at Symbiotic

• Backend: Python 3.12+, Django, REST API
• Frontend: TypeScript, React SPA
• Database: PostgreSQL
• Infra: AWS, Docker, Terraform
• Tooling: Sentry, observability, internal analytics
• Testing: 94% backend coverage

Why Join Us

• ESOP
• 100% health insurance
• Swile meal card
• RTT + paid vacation
• €500 equipment budget
• 2 remote days/week
• Collaborative, no-ego engineering team
• Deep-tech product with real impact
• Fast hiring process ( 2 weeks)

Hiring Process

1. Intro call with Blanche (Talent Acquisition) — 30 min
2. Interview with Abir (Engineering Manager) — 45 min
3. On-site technical test — 2h
4. Culture fit + team lunch — 2h
5. Offer