AI .Net Software Engineer | Senior

ABOUT THE OPPORTUNITY

We are looking for a Senior AI Software Engineer to join a technology team in the capital markets infrastructure sector, contributing to cross-functional services and foundational components used across multiple business areas. This role combines backend software engineering with applied AI, supporting the design, deployment and optimization of scalable solutions based on machine learning, NLP and large language models.

WHAT YOU WILL DO

- Design, build and maintain scalable backend services using C# and .NET, integrating AI capabilities into business applications.

- Translate business requirements into reliable software solutions and applied AI use cases, with a focus on NLP, generative AI and large language models.

- Fine-tune, deploy and optimize pre-trained models for specific product and platform needs.

- Create proofs of concept for research and development initiatives, using notebooks and data analysis to validate technical approaches.

- Design and integrate cloud-native architectures, APIs, microservices and production-ready machine learning pipelines.

- Develop and refine prompts for LLM-based solutions, testing model behavior and parameters to improve output quality.

- Apply AI governance practices, guardrails, auditing mechanisms, secure usage principles and data privacy controls.

- Collaborate with product owners and cross-functional teams to support delivery timelines and solution quality.

- Conduct code reviews, support technical mentoring and contribute to documentation for software architecture and AI components.

- Prioritize issue resolution in line with service expectations, while identifying risks, technical debt and improvement opportunities.

WHAT WE ARE LOOKING FOR

- Degree in Computer Science, Engineering or a related field.

- Minimum 5 years of hands-on software development experience, including C# and .NET or .NET Core.

- At least 2 years of experience in machine learning, generative AI or data science.

- Strong problem-solving ability, structured analysis and a solution-oriented mindset.

- Experience designing scalable systems, databases and production-oriented applications.

- Ability to work in Agile or Scrum environments with multidisciplinary teams.

- Professional working proficiency in English, minimum B2 level.

- Availability to work in a hybrid model, including three days per week at the office in Porto.

- Responsible, collaborative and quality-driven approach, with openness to mentoring and knowledge sharing.

TECHNICAL SKILLS

- C#

- .NET

- .NET Core

- Python

- Machine Learning

- Generative AI

- Data Science

- NLP

- Large Language Models

- GPT

- Transformers

- Hugging Face

- TensorFlow

- PyTorch

- Prompt engineering

- Model fine-tuning

- MLOps concepts

- Jupyter

- Cloud platforms

- AWS

- Azure

- AWS SageMaker

- AWS Bedrock

- Microservices

- API security

- Docker

- Kubernetes

- DevOps

- CI/CD pipelines

- Data privacy

- AI guardrails

- Trusted AI practices

- Agile

- Scrum

NICE TO HAVE

- Relevant AWS, Azure or AI certifications.

- Experience building production-grade AI solutions.

- Exposure to AI governance frameworks.

- Experience with Java and Spring Boot.

WHAT WE OFFER

- Private health insurance from day one, with no waiting periods and optional family extension.

- Confidential and free mental health support through a dedicated partner, including psychological support, content and live sessions.

- Continuous training and certification support throughout your journey, encouraging structured growth and long-term capability building.

- Flexibility whenever the role and project context allow it, supporting sustainable performance and daily balance.

- Family support measures, including childcare vouchers.

- Community moments, shared milestones and leadership presence when it matters most.

- Upskilling opportunities in quality management, information security, AI governance and cybersecurity best practices.

EQUAL OPPORTUNITY

Hexa is committed to equal opportunity and inclusive recruitment. We value different backgrounds, perspectives and experiences, and we align our practices with the principles of the Portuguese Diversity Charter.

HEXA LIFE

At Hexa, we are all Builders. You will be part of a culture based on honesty, mutual support and agility, where people are encouraged to contribute, improve and build meaningful solutions with responsibility, transparency and shared ambition.