Lead Software Engineer, AI SaaS Platform (Full-Stack & ML)

ArcaScience | Paris 13e (Future4Care) | Hybrid, 2-3 days remote/week | CDI, Cadre | 70K-80K€+var

Who We Are

ArcaScience is a leading French AI startup using biomedical data to predict a drug's risk and efficacy before it reaches the patient, then re-evaluate that risk once patients are taking it. Our impact is concrete: accelerating drug development and helping patients get the right drug.

We run our own AI models that analyze the benefit-risk profile of molecules for specific pathologies and patient groups, and tomorrow, individual patients. We are significantly accelerating our three-year growth and global expansion from the Future4Care healthtech hub.

The Role

We are hiring one Tech Lead to own our AI SaaS platform end to end, from a high-traffic, secure product surface down to the NLP models and data pipelines that power it.

You will lead a cross-functional team (fewer than 10 engineers and ML/Data engineers), set technical direction across full-stack and ML, and stay close enough to the code to ship. You will work daily with scientists, biologists, product, and regulatory.

This is not two jobs bolted together: the best AI products come from one person who can reason from the user-facing feature down to the model that powers it.

What You'll Own

Platform & Product (Full-Stack SaaS)

Ship scalable, maintainable features across the stack (React, Node.js, Python).

Architect for high traffic, speed, and scalability, with security and compliance built in by design.

Stay product-oriented: ship valuable features fast to hit short time-to-market.

AI / ML & Data

Train and improve NLP models: classification, named entity recognition (NER), relation and text extraction, entity linking, standardization, aggregation.

Own the full NLP/ML lifecycle: training, evaluation, deployment, monitoring.

Run MLOps with tools like MLflow, Langfuse, and LiteLLM (experiment tracking, observability, cost control, validation automation), and integrate LLM APIs into production.

Pipelines & Reliability (SRE / DevOps)

Own the data pipelines behind delivery, handling hundreds of daily workflows over millions of biomedical documents.

Ensure high availability and performance in production, and drive data quality and compliance to strict medical standards.

Leadership

Manage, mentor, and grow the team; deliver solutions aligned with business goals.

Communicate clearly with technical and non-technical stakeholders (CTO, product, regulatory, customers).

What Success Looks Like

In your first year: platform and pipelines mapped and shipping faster, a clean MLOps loop in place (tracking, observability, evaluation), measurable gains in model quality and delivery speed, a grown team, and benefit-risk analysis moving toward real-time. We value judgment over heroics: what to ship now, what to defer, what to cut.

Must-Have Qualifications

We want a strong full-stack SaaS engineer with a real ML track record, not five specialists in one. Full-stack depth and hands-on NLP are the non-negotiable core; the rest is learnable on the job.

Degree in Computer Science / Engineering or equivalent, with 8+ years in software engineering including high-traffic SaaS platforms.

Strong full-stack experience: a modern front-end (React preferred, Vue or Angular accepted) plus Node.js and Python backends.

3+ years of professional Python.

A genuine AI/ML track record: you have personally trained and shipped NLP models (NER, extraction, classification, standardization), not just consumed APIs.

Hands-on MLOps: experiment tracking and LLM observability (MLflow, Langfuse, LiteLLM, or equivalents).

REST, NoSQL, DevOps fundamentals, cloud (AWS, GCP, or Scaleway), and containerization (Docker, Kubernetes).

Git, plus a real understanding of accessibility and security/compliance.

Product orientation: a demonstrated ability to ship the right thing fast.

Excellent English (French a plus) and proven team leadership.

Strong Pluses

Our data stack: FastAPI, SpaCy, Spark NLP, Airflow, S3, PostgreSQL, Elasticsearch, Qdrant.

IaC and CI/CD: GitLab CI, Terraform, Ansible, AWS EKS.

Regulated/high-compliance experience (medical, pharma, fintech), Agile and TDD, vector search/RAG and LLM extraction pipelines.

What We Offer

A multicultural team of engineers, scientists, and biologists, and a broad mandate: own product and ML, not a narrow slice.

Hybrid flexibility (2-3 days remote/week) from Future4Care in Paris 13e.

Package: 70K-80K€ gross/year, plus 13th month, performance bonuses, RTT, daily transport coverage, work-from-home allowance.

Onboarding and training in Pharmaceutical Sciences or AI, tailored to your background.

Hiring Process

30-45 min intro call with Our CTO

Online technical and personality assessment.

Operational interview with an ArcaScientist and/or a team meal.

Final on-site interview to review the test and meet executives.

Welcome aboard.

Job Type: Full-time

Pay: 75.00€ - 80.00€ per year

Education:

Master's (Required)

Work Location: Hybrid remote in Paris 13e (75)