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Senior ML/LLM Engineer (API & Fullstack) - English Mandatory

Sopra Steria

Senior ML/LLM Engineer (API & Fullstack) - English Mandatory

full-timePosted: Jan 23, 2026

Job Description

Description

This role is for a Senior ML/LLM Engineer with strong data science capabilities and a significant focus on API development and full-stack engineering principles. They will be responsible for the end-to-end lifecycle of machine learning solutions, from model conception and development to building robust, scalable APIs and integrating them into production applications.

 

     

    Qualifications

    Data Science, Model Development & LLM Expertise:

    • Statistical Models & Machine Learning: Develop, test, and validate statistical and machine learning models in Python. Explore, select, and prepare datasets, including feature engineering using libraries like NumPy, Pandas, Polars, and SciPy.
    • Advanced ML Libraries: Develop and implement classification, regression, and other predictive models leveraging libraries such as Scikit-learn, XGBoost, LightGBM, CatBoost, and deep learning frameworks like TensorFlow/Keras and PyTorch.
    • Natural Language Processing (NLP) & Text Mining: Utilize NLP techniques to extract insights from unstructured text, employing libraries like NLTK, spaCy, Hugging Face Transformers, and Sentence Transformers.
    • Large Language Models (LLMs):
      • Architect and implement solutions using LLMs (e.g., GPT-4, Claude 3, Llama 3, Gemini) via APIs or by fine-tuning open-source models for tasks like extraction, classification, summarization, content generation, and conversational AI.
      • Proficiency with LLM application development frameworks such as LangChain, LlamaIndex, and Haystack for building complex, orchestrated LLM workflows.
      • Skilled in prompt engineering, fine-tuning techniques (e.g., LoRA, QLoRA), and designing Retrieval Augmented Generation (RAG) systems.
      • Experience with vector databases (e.g., Pinecone, Weaviate, ChromaDB, FAISS) for semantic search and knowledge retrieval.

    Additional Information

    What do we have for you?

    • Full time permanent contract
    • 23 days annual leave
    • Continuous training: technical and transversal skills and languages. We provide access to several certifications and accreditations and learning programs with our main technological partners, online platforms and more. 
    • Life and accident insurance.
    • Flexible benefits program (health insurance, meal vouchers, childcare vouchers, mobility, and training)
    • “Privilige Club” access, where you will find deals for several brands.
    • Detailed and personalized onboarding. We’ll be with you in every step of the way so you can feel #soprano from the very beginning.
    • Recreational spaces in our offices because work and fun go hand in hand.
    • Companionship and great working environment because we know how important the power of togetherness is.

    And most importantly you´ll have the opportunity to develop your professional career with us. Together we’ll create an individualized career development plan. We’ll establish goals and we’ll make sure we achieve them together. Your priorities will be ours. 

    Your voice will be heard! - Join us and be part of something bigger!

    The world is how we shape it

    Adquirimos el compromiso de respetar la diversidad, creando un ambiente de trabajo inclusivo y aplicando políticas que favorezcan la inclusión y promuevan el respeto social y cultural en cuestiones de género, edad, funcional, orientación sexual y religión con igualdad de oportunidades.

    Company Description

    Your career starts now…

    We are renowned European world leader in consulting, digital services and software development with 56.000 employees in almost 30 countries and more than 4.000 employees in Spain.
    We focus on people; their growth and their professional development is what makes us grow and improve constantly.

    We are passionate about the digital world and just like you we are looking for the greatest adventures. We want your day to day to be your source of inspiration. We want you to learn, to have fun, to grow and most importantly to enjoy to the fullest. 

    If you want to be a part of a “Great Place to work” company ...just keep reading!

    Locations

    • Barcelona, Connecticut, Spain

    Salary

    Estimated Salary Rangemedium confidence

    40,000 - 65,000 EUR / yearly

    Source: AI Estimation

    * This is an estimated range based on market data and may vary based on experience and qualifications.

    Skills Required

    • Pythonintermediate
    • NumPyintermediate
    • Pandasintermediate
    • Polarsintermediate
    • SciPyintermediate
    • Scikit-learnintermediate
    • XGBoostintermediate
    • LightGBMintermediate
    • CatBoostintermediate
    • TensorFlow/Kerasintermediate
    • PyTorchintermediate
    • NLTKintermediate
    • spaCyintermediate
    • Hugging Face Transformersintermediate
    • Sentence Transformersintermediate
    • LangChainintermediate
    • LlamaIndexintermediate
    • Haystackintermediate
    • Pineconeintermediate
    • Weaviateintermediate
    • ChromaDBintermediate
    • FAISSintermediate
    • prompt engineeringintermediate
    • LoRAintermediate
    • QLoRAintermediate
    • RAGintermediate

    Required Qualifications

    • Senior ML/LLM experience (experience)
    • English mandatory (experience)
    • Data science expertise (experience)
    • Fullstack/API development (experience)

    Responsibilities

    • End-to-end ML lifecycle
    • Model development
    • API building
    • Production integration

    Benefits

    • general: Full time permanent contract
    • general: 23 days annual leave
    • general: Continuous training
    • general: Life and accident insurance
    • general: Flexible benefits
    • general: Privilege Club
    • general: Onboarding
    • general: Recreational spaces
    • general: Career development

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    Sopra Steria logo

    Senior ML/LLM Engineer (API & Fullstack) - English Mandatory

    Sopra Steria

    Senior ML/LLM Engineer (API & Fullstack) - English Mandatory

    full-timePosted: Jan 23, 2026

    Job Description

    Description

    This role is for a Senior ML/LLM Engineer with strong data science capabilities and a significant focus on API development and full-stack engineering principles. They will be responsible for the end-to-end lifecycle of machine learning solutions, from model conception and development to building robust, scalable APIs and integrating them into production applications.

     

       

      Qualifications

      Data Science, Model Development & LLM Expertise:

      • Statistical Models & Machine Learning: Develop, test, and validate statistical and machine learning models in Python. Explore, select, and prepare datasets, including feature engineering using libraries like NumPy, Pandas, Polars, and SciPy.
      • Advanced ML Libraries: Develop and implement classification, regression, and other predictive models leveraging libraries such as Scikit-learn, XGBoost, LightGBM, CatBoost, and deep learning frameworks like TensorFlow/Keras and PyTorch.
      • Natural Language Processing (NLP) & Text Mining: Utilize NLP techniques to extract insights from unstructured text, employing libraries like NLTK, spaCy, Hugging Face Transformers, and Sentence Transformers.
      • Large Language Models (LLMs):
        • Architect and implement solutions using LLMs (e.g., GPT-4, Claude 3, Llama 3, Gemini) via APIs or by fine-tuning open-source models for tasks like extraction, classification, summarization, content generation, and conversational AI.
        • Proficiency with LLM application development frameworks such as LangChain, LlamaIndex, and Haystack for building complex, orchestrated LLM workflows.
        • Skilled in prompt engineering, fine-tuning techniques (e.g., LoRA, QLoRA), and designing Retrieval Augmented Generation (RAG) systems.
        • Experience with vector databases (e.g., Pinecone, Weaviate, ChromaDB, FAISS) for semantic search and knowledge retrieval.

      Additional Information

      What do we have for you?

      • Full time permanent contract
      • 23 days annual leave
      • Continuous training: technical and transversal skills and languages. We provide access to several certifications and accreditations and learning programs with our main technological partners, online platforms and more. 
      • Life and accident insurance.
      • Flexible benefits program (health insurance, meal vouchers, childcare vouchers, mobility, and training)
      • “Privilige Club” access, where you will find deals for several brands.
      • Detailed and personalized onboarding. We’ll be with you in every step of the way so you can feel #soprano from the very beginning.
      • Recreational spaces in our offices because work and fun go hand in hand.
      • Companionship and great working environment because we know how important the power of togetherness is.

      And most importantly you´ll have the opportunity to develop your professional career with us. Together we’ll create an individualized career development plan. We’ll establish goals and we’ll make sure we achieve them together. Your priorities will be ours. 

      Your voice will be heard! - Join us and be part of something bigger!

      The world is how we shape it

      Adquirimos el compromiso de respetar la diversidad, creando un ambiente de trabajo inclusivo y aplicando políticas que favorezcan la inclusión y promuevan el respeto social y cultural en cuestiones de género, edad, funcional, orientación sexual y religión con igualdad de oportunidades.

      Company Description

      Your career starts now…

      We are renowned European world leader in consulting, digital services and software development with 56.000 employees in almost 30 countries and more than 4.000 employees in Spain.
      We focus on people; their growth and their professional development is what makes us grow and improve constantly.

      We are passionate about the digital world and just like you we are looking for the greatest adventures. We want your day to day to be your source of inspiration. We want you to learn, to have fun, to grow and most importantly to enjoy to the fullest. 

      If you want to be a part of a “Great Place to work” company ...just keep reading!

      Locations

      • Barcelona, Connecticut, Spain

      Salary

      Estimated Salary Rangemedium confidence

      40,000 - 65,000 EUR / yearly

      Source: AI Estimation

      * This is an estimated range based on market data and may vary based on experience and qualifications.

      Skills Required

      • Pythonintermediate
      • NumPyintermediate
      • Pandasintermediate
      • Polarsintermediate
      • SciPyintermediate
      • Scikit-learnintermediate
      • XGBoostintermediate
      • LightGBMintermediate
      • CatBoostintermediate
      • TensorFlow/Kerasintermediate
      • PyTorchintermediate
      • NLTKintermediate
      • spaCyintermediate
      • Hugging Face Transformersintermediate
      • Sentence Transformersintermediate
      • LangChainintermediate
      • LlamaIndexintermediate
      • Haystackintermediate
      • Pineconeintermediate
      • Weaviateintermediate
      • ChromaDBintermediate
      • FAISSintermediate
      • prompt engineeringintermediate
      • LoRAintermediate
      • QLoRAintermediate
      • RAGintermediate

      Required Qualifications

      • Senior ML/LLM experience (experience)
      • English mandatory (experience)
      • Data science expertise (experience)
      • Fullstack/API development (experience)

      Responsibilities

      • End-to-end ML lifecycle
      • Model development
      • API building
      • Production integration

      Benefits

      • general: Full time permanent contract
      • general: 23 days annual leave
      • general: Continuous training
      • general: Life and accident insurance
      • general: Flexible benefits
      • general: Privilege Club
      • general: Onboarding
      • general: Recreational spaces
      • general: Career development

      Target Your Resume for "Senior ML/LLM Engineer (API & Fullstack) - English Mandatory" , Sopra Steria

      Get personalized recommendations to optimize your resume specifically for Senior ML/LLM Engineer (API & Fullstack) - English Mandatory. Takes only 15 seconds!

      AI-powered keyword optimization
      Skills matching & gap analysis
      Experience alignment suggestions

      Check Your ATS Score for "Senior ML/LLM Engineer (API & Fullstack) - English Mandatory" , Sopra Steria

      Find out how well your resume matches this job's requirements. Get comprehensive analysis including ATS compatibility, keyword matching, skill gaps, and personalized recommendations.

      ATS compatibility check
      Keyword optimization analysis
      Skill matching & gap identification
      Format & readability score

      Tags & Categories

      IT ServicesConsultingIT ServicesConsulting

      Answer 10 quick questions to check your fit for Senior ML/LLM Engineer (API & Fullstack) - English Mandatory @ Sopra Steria.

      Quiz Challenge
      10 Questions
      ~2 Minutes
      Instant Score

      Related Books and Jobs

      No related jobs found at the moment.