The technical challenge

This is not a conventional applied-AI problem.

Biological data is heterogeneous, noisy, sparse and longitudinal. Measurements are incomplete, collected across modalities and timescales, and individual trajectories vary substantially.

The core challenge is to learn meaningful biological dynamics from incomplete multimodal observations and understand how individual trajectories evolve under different conditions.

We are looking for someone who can go beyond applying existing models and help define the right computational framework for the problem.

Why Eldena

The opportunity is to help define a new technical category: computational models for dynamic skin biology. Skin is a uniquely tractable system to model. It can be measured repeatedly and non-invasively, is continuously exposed to environmental and individual factors, and responds observably to interventions. We generate real-world multimodal data and work with scientific, clinical and industrial partners across dermatology, pharmaceuticals and cosmetic research.

The role

We are looking for a CTO & Technical Co-Founder to take ownership of Eldena's technology and lead its next stage of development.

Eldena is not starting from zero. We have an existing MVP, initial data and modelling infrastructure, active data generation and ongoing scientific work. Your first responsibility will be to understand what has been built, assess it critically and define what needs to be strengthened, redesigned or developed next.

You will work directly with the CEO, CSO and scientific partners, with responsibility across data, modelling, infrastructure, products and technical governance.

This remains a hands-on role. You will work directly with models, data and architecture while progressively building the technical organization around you.

What you will own

AI and modelling

Define Eldena's modelling strategy for multimodal and longitudinal biological data. Lead the development, training and evaluation of the core models, including uncertainty, robustness and generalization. Establish clear criteria for when a model is ready to move from research into product or scientific use.

Scientific validation

Build rigorous validation protocols with the CSO and scientific partners. Define benchmarks, baselines, acceptance criteria and evaluation datasets. Ensure that model scores and predictions are validated against relevant measurements and scientific or clinical references, and that performance claims remain supported by evidence.

Data, platform and engineering

Own the architecture connecting data acquisition, data infrastructure, model development and Eldena products. Build reliable pipelines for multimodal and longitudinal data, together with training, inference, APIs, experiment tracking, monitoring and reproducibility. Make pragmatic decisions about what Eldena should build internally, reuse or develop with partners.

Security, privacy and technical governance

Build security, privacy and data governance into the technical architecture. Establish appropriate controls for access, traceability, data protection, model governance and reproducibility. Work with the CEO and external specialists on GDPR requirements and prepare the technical organization for future quality, security and regulatory requirements as Eldena scales.

Technical leadership and team

Set Eldena's engineering and research standards. Recruit and lead the future AI, data and software team. Decide how technical resources should be allocated and ensure that research priorities remain compatible with product and business priorities.

External technical leadership

Represent Eldena's technology alongside the CEO in discussions with scientific partners, clients, investors and strategic collaborators. Explain and defend technical choices clearly, contribute to technical due diligence, strategic partnerships and key client discussions, and adapt the level of discussion to researchers, technical teams, executives and investors.

The person we hope to find

We are looking for a strong technical builder with research depth and the judgement required to become Eldena's technical leader.

You should have deep expertise in modern machine learning and experience building real systems. We are particularly interested in experience with multimodal learning, longitudinal or temporal modelling, representation learning, scientific machine learning, probabilistic modelling and uncertainty.

You may come from an AI research lab, deeptech company, startup or research environment. A PhD and strong publications are valuable, but neither is required. We care about the quality of what you have built, the decisions you have owned and your ability to work across research and engineering.

You do not need to be a skin biologist. You do need the curiosity and scientific discipline to work closely with domain experts, understand experimental constraints and distinguish what a model appears to learn from what the evidence actually supports.

Experience with sensitive biological or health-related data, security, privacy, regulated environments or quality systems is an advantage.

We are looking for someone who can operate as a founder: hands-on when necessary, able to make difficult technical decisions, comfortable representing the technology externally and capable of building the organization that will eventually operate without depending on them for every technical decision.

Practical information

• Location: Paris
• Commitment: Full-time
• Role: CTO & Technical Co-Founder
• Compensation: €80k–€120k base salary, depending on profile and experience, plus meaningful founder-level equity

If you want to work on one of the hardest problems at the intersection of AI and biology, we would like to hear from you.