Senior Data Scientist | AI Engine

At Wellhub (formerly Gympass) (Permanent), in Lisbon, Portugal

Salary : €55.000 - €65.000

Expires at : 2025-12-09

Remote policy : Full remote

We are hiring a “Senior Data Scientist” to our AI Engine team in Portugal !

We are looking for a talented and motivated Data Scientist to join our team in Brazil / Portugal and contribute to groundbreaking projects in the field of Generative AI! In this role, you will help shape the future of AI-powered wellness solutions by leveraging Generative AI, fine-tuning of LLMs, and evaluation of Agentic systems.

As a Data Scientist in the CARE team, you will be at the forefront of innovation, developing cutting-edge Agentic AI that enhance and personalize the wellness journey for millions of Wellhub subscribers. Your work will directly contribute to advancing AI’s role in wellness, making it more adaptive, impactful, and transformative. You will collaborate with a multidisciplinary team of engineers and domain experts to create innovative AI applications and solve real-world problems.

YOUR IMPACT

• Model Development & Fine tuning : Understanding of state-of-the-art deep learning techniques, such as Transformers architectures and attention mechanisms, and knowledge of  fine-tuning LLMs for enhanced model performance, using techniques such as  LoRA, QLoRA, among others.
• Function Calling & Tool Use : Design and implement structured function calling mechanisms within LLMs to enable dynamic interactions with APIs, databases, and retrieval-augmented generation (RAG) pipelines.
• Prompt Engineering : Craft clear instructions that help our models understand exactly what we need, creating reusable templates and testing against edge cases.
• Data Preparation : Preprocess, analyse, and curate high-quality datasets to train and fine-tune both embedding and generative models.
• Evaluation and Testing : Develop robust evaluation frameworks to assess agentic AI performance, combining automated evaluation (LLM-as-judge), adversarial testing, human-in-the-loop evaluations, and custom behavioral metrics.
• LLM Observability : Establish monitoring systems that track LLM behavior in production, capturing key metrics around information retrieval, hallucinations, and latency.
• Research and Innovation : Stay current with the latest research in generative AI,, share insights with the team, test promising approaches, and help make us better.
• Deployment : Collaborate with engineering teams to deploy models in scalable and efficient production environments.

Live the mission : inspire and empower others by genuinely caring for your own wellbeing and your colleagues. Bring wellbeing to the forefront of work, and create a supportive environment where everyone feels comfortable taking care of themselves, taking time off, and finding work-life balance.

Main requirements

We recognize that individuals approach job applications differently. We strongly encourage all aspiring applicants to go for it, even if they don't match the job description 100%. We welcome your application and will be delighted to explore if you could be a great fit for our team. For this specific role, please note that prior experience in Python and SQL are mandatory requirements.

Benefits & Perks

We're a wellness company that is committed to the health and well-being of our employees. Our benefits include :

WELLHUB : We believe in our mission and encourage our employees and their families to take care of their wellbeing too. Access digital fitness programs and online wellness resource, digital fitness programs, and online wellness resources for meditation, nutrition, mental health support, and more. You will receive the Gold plan at no cost, and other premium plans will be significantly discounted.

FITNESS : Additional fitness subsidy to access onsite gyms and fitness studios.

FLEXIBLE WORK :   At Wellhub, flexibility fosters a happier, healthier, and more productive work environment for everyone. As a Flexible First company, we offer two work model options : flexible hybrid and full remote, and make the office a place for collaboration, community, and team building. The model for this role can be discussed with your recruiter and hiring manager. We offer all employees a home office stipend and a monthly flexible work allowance to help cover the costs of working from home.

FLEXIBLE SCHEDULE : We understand that together, Wellhubbers and their leaders can make the best decisions for their own individual scopes. This includes flexibility to adjust their working hours based on their personal schedule, time zone, and business needs.

PAID TIME OFF : We know how important it is to take time away from work to recharge. Employees receive a minimum of 25 days paid holiday per year with an additional day for each year of tenure (up to 5) in addition to annual holidays (including an extra holiday on your birthday!).

PARENTAL LEAVE : Welcoming a new child is one of the most special moments in your life and we want our employees to take the time to be present and enjoy their growing family. We offer 100% paid parental leave to all new parents and extended maternity leave.

CAREER GROWTH : Outstanding opportunities for personal and career growth. That means we maintain a growth mindset in everything we do and invest deeply in employee development.

CULTURE : An exciting and supportive environment filled with passionate individuals from all over the world! You’ll partner with global colleagues and share in the success of a high-growth technology company disrupting the health and wellness space. Our value-based culture of trust, flexibility, and integrity makes this possible every day.