Founding Fullstack Engineer @Rose
Hexa
Paris
1 day ago
engineering
🚀 Hexa
Rose is a startup launched by Hexa, the Paris-based startup studio founded in 2011 that has created over 40 companies including Front, Aircall, Spendesk, and Swan (3 unicorns, +$700M raised, portfolio valuation >$5B).
With €29M in funding finalized in 2025 and the goal to launch 30 startups per year by 2030, Hexa offers a unique environment: shared resources, expert network, and an ecosystem of hundreds of engineers and founders.
🎯 Rose in a nutshell
The problem: 85% of B2B website visitors leave without interaction. Meanwhile, they use ChatGPT and Perplexity to compare solutions before even contacting you.
Our mission: Transform B2B websites into intelligent conversational assistants that engage 100% of traffic, capture quality zero-party data, and increase demo conversions.
Our approach: Unlike traditional chatbots (~5% engagement), Rose achieves 20%+ engagement through an integrated assistant experience, not an intrusive popup.
Our clients: Pennylane, Mayday, AB Tasty are already using Rose in production.
💼 The role
You'll join Rose as the first Founding Engineer to build the platform alongside, Benoit, CTO/Cofounder.
You'll work on cutting-edge technical challenges in an environment where every line of code has a direct impact on the product and users.
Your missions
Co-build the technical architecture with the CTO (backend, frontend, infrastructure)
Develop core features: conversational AI engine, interactive experiences, third-party integrations, back-office
Make technical choices that structure the platform for the next 5 years
Participate to the implementation of RAG (Retrieval-Augmented Generation) systems in production with Vector database and knowledge graph
Optimize real-time performance
Develop guardrails and testing mechanisms to ensure AI response quality
Build bidirectional integrations with CRMs (Salesforce, HubSpot)
Orchestrate calendar systems (Calendly, Chili Piper) and analytics (Posthog)
Participate in product decisions and user exchanges
Tech Stack
Tech Philosophy
👤 Who we're looking for
Mindset
Nice to have
🎁 What we offer
Recruitment process
We respect your time with an efficient ~3 week process:
- Discovery HR interview (30 min) - Rose presentation, discussion about your background
- CTO interview (45min) with the CTO - Discussion about your experiences, technical approaches
- Tech assessment (2-3h max) - Realistic technical problem related to our challenges (remote possible)
- Final meeting (2h) at the office - Technical deep dive, culture fit with Johary, CEO & Florent, Partner Hexa
- References and formal offer
Sponsored
