Fullstack Software Engineer (Python / TypeScript / React)

📍 Paris (Morning Laffitte) | Full-time | 2 remote days per week

🌍 Tech Team | Role split 70% backend / 30% frontend

About Symbiotic Security

Symbiotic Security is a cybersecurity startup helping developers write secure code through an AI-powered assistant integrated into their IDE and CI/CD pipelines. Our solution has two unique strengths: it provides developers with interactive training to understand vulnerabilities as they code, and it automatically detects and remediates security flaws introduced by generative AI tools such as GitHub Copilot.

➡️ Founded in April 2024

➡️ 16 team members split between Paris (Tech team) and New York (Sales team)

➡️ Goal: 15 new hires by the end of 2026

Our offices are located at Morning Laffitte (Paris 9ᵗʰ) — bright open spaces with collaborative areas, a friendly atmosphere, and a focus on productivity.

Tech Stack & Environment

Backend: Python 3.12+ / Django (monolith, REST API)
Frontend: TypeScript / React (SPA) for the frontend of the SaaS platform,
Typescript for the IDE plugin
Database: PostgreSQL
Architecture: Monolithic - Hexagonal, DDD being introduced
Tests: 94% backend coverage, 100% business logic covered
Tools: Sentry, logs, traces, internal analytics
Satellite services: CLI tools & AI agents written in Python

Your Mission

Contribute to both the backend (70%) and frontend (30%) of our SaaS product.
Participate in the design and evolution of our hexagonal architecture and DDD approach.
Collaborate closely with Abir (Engineering Manager), Minh Thang (Tech lead) and Édouard (CTO) on technical and product decisions.
Work on diverse projects: REST APIs, CLI tools, AI agents, performance optimization.
Lead continuous improvement initiatives, such as code reviews, automated testing, and release management.
Offer technical guidance to team members, fostering a culture of learning and professional development.

What We’re Looking For

Core Skills

Master's degree in Computer Science or related field.
Proven experience (min 5 years) as a software engineer, with a strong track record of designing and delivering complex software systems, Python and TypeScript required ✅
Demonstrated expertise in backend development using Python. An experience of Django would be a strong plus.
Demonstrated expertise in frontend development using Typescript / React.
Solid SQL knowledge (PostgreSQL preferred)

Appreciated

Experience working with Product Manager, Product Designer, or UI/UX person.
Strong grasp of clean code principles (SOLID, DRY, YAGNI)
Understanding or curiosity for DDD
Monitoring / logging / API optimization = big plus
Comfortable using LLMs (ChatGPT, Copilot, Claude)

Soft Skills & Mindset

Early-stage startup mindset: autonomous, fast, impact-driven
Curious, rigorous, and eager to understand before acting
Strong communicator, collaborative, no ego
Capable of challenging ideas and defending opinions constructively
Product-oriented with a desire to build meaningful software
Work-life balance valued

What You’ll Have Achieved

Timeframe Key Milestones

3 months First features shipped, ramp-up on the stack, contribution to testing pipeline

6 months Leading a technical scope, improving architecture, driving performance or monitoring initiatives

12 months Recognized internal expert / coach within the team

Methodology & Culture

Agile-ish organization (2-week sprints, continuous releases)
Systematic code reviews
Occasional pair programming
Mix of maintenance, new features, and R&D work
Monthly “Bug Day” (stress testing the product)
“Cool down period” planned for internal tech projects

💡 AI culture: every developer is encouraged to use ChatGPT, Copilot, or Claude as part of their workflow.

Team

Our product team brings together diverse profiles working collaboratively: fullstack engineers, AI engineers, cybersecurity experts, product managers, and product designers: all coming from different backgrounds.

Team culture:

Collaboration > hierarchy
Technically demanding but kind environment
No-ego culture
Strong product–tech alignment

Compensation & Benefits

💰 BSPCE (equity) available

🏥 100% health insurance coverage

🍽️ Swile meal card

💻 €500 equipment budget

🚲 Allowance for Sustainable Commuting (e.g., cycling, carpooling, public transport)

🏖️ RTT + paid vacation

🏡 2 remote days per week

🪴 Important opportunities for career advancement and professional development by being a pioneer within a new company.

🧑‍🔬 Strong product & engineering culture in the company.

🥂 Vibrant and inclusive company culture with regular team outings and events.

☝🏽 Chance to make a meaningful impact and shape the future of Symbiotic.

👭 Referral bonus: €2,000

Hiring Process

We respect your time and will make it quick and efficient. All of that will be completed within two weeks.

Call with our Talent Acquisition - Blanche - 30 minutes
Meeting with our Engineering Manager - Abir - 45 minutes to 1 hour.
On-site technical test with our tech lead - Minh Thang - 1,5 hour.
Culture fit - Meeting with the CTO and lunch with the team - 2 hours
Formal hiring proposal.

Senior Software Engineer

Job Description