The Role
As a Senior Software Engineer, you'll build product features using JavaScript/TypeScript, contribute to system design, and lead technical initiatives. Collaboration with engineers is key, and you will also work on Python services when necessary.
Summary Generated by Built In
📍 Paris (Morning Laffitte) | Full-time | 2 remote days per week
🌍 Tech Team | Role split Full JS (Node/React) with mission-first contributions on Python services when needed
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.
Our main products:
- Symbiotic Code — https://www.symbioticsec.ai/products/symbiotic-code
- Symbiotic Flow — https://www.symbioticsec.ai/products/symbiotic-flow
➡️ Founded in April 2024
➡️ 24 team members split between Paris (Tech team) and New York (Sales team)
➡️ Goal: 10 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.
- Build and ship product features across our JavaScript/TypeScript stack (Node + React) for Symbiotic Code.
- Contribute to performance, reliability, and overall system design as we scale.
- Collaborate closely with Abir (Engineering Manager), Minh Thang (Tech lead) and Édouard (CTO) on technical and product decisions.
- Work on diverse scopes: APIs, portal features, IDE experience, CLI workflows, and internal tooling.
- Lead continuous improvement initiatives: code reviews, automated testing, CI quality gates, and release practices.
- Offer technical guidance to the team and help raise the quality bar.
Mission-first mindset: we look for engineers who are ready to “cross the aisle”. If you’re a JS expert, you should be open to learning and contributing to our Python services when the mission requires it.
3 months First features shipped on the JS stack, strong ownership on a scope, confident navigation of the codebase and dev workflow
6 months Leading a technical scope end-to-end, raising testing discipline, driving performance/reliability improvements
12 months Recognized internal expert / coach on JS/TS architecture and delivery at scale
⚙️ Tech Stack & Environment
- Languages: JavaScript / TypeScript (primary)
- Frontend: React (portal / SaaS experience)
- Backend: Node.js (TypeScript) for APIs and services
- Testing: strong testing discipline (unit/integration, CI-driven)
- Nice to have: Python, Bun, OpenTUI
- Observability: logs / traces / monitoring (tooling in place; experience appreciated)
- Proven experience (typically 5+ years) as a software engineer delivering production systems.
- Strong track record in TypeScript/JavaScript ✅
- Solid experience with React and Node.js (fullstack ownership)
- Strong engineering fundamentals: system thinking, pragmatic architecture, clean code, and delivery discipline
- Strong testing discipline and ability to design for maintainability
- Experience designing and operating asynchronous/distributed systems
- Observability / performance optimization / reliability mindset
- Comfort using LLM tools (ChatGPT, Copilot, Claude) responsibly
- Ability (and curiosity) to contribute to Python services when needed
- 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
- Agile 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.
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.
- 👩💻 MT – Lead Engineer
- 👩💻 Abir – Engineering Manager
- 👨💻 Édouard – CTO
Team culture:
- Collaboration > hierarchy
- Technically demanding but kind environment
- No-ego culture
- Strong product–tech alignment
💰 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
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
- Technical “case” (Algorithm live coding + System Design) + debrief — 2 hours
- Culture fit - Meeting with the CTO and lunch with the team — 2 hours
- Formal hiring proposal
Skills Required
- Proven experience as a software engineer delivering production systems for typically 5+ years
- Strong track record in TypeScript/JavaScript
- Solid experience with React and Node.js (fullstack ownership)
- Strong engineering fundamentals: system thinking, pragmatic architecture, clean code, and delivery discipline
- Strong testing discipline and ability to design for maintainability
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The Company
What We Do
Symbiotic Security is an AI coding company that provides a real-time security platform for software developers. It offers an AI code generation agent that embeds security enforcement directly into the workflow, enabling real-time detection and remediation of security vulnerabilities.
