Senior Software Engineer

Who we areWe are Fluxon, a product development team founded by ex-Googlers and startup founders. We offer full-cycle software development: from ideation and design to build and go-to-market. We partner with visionary companies, ranging from fast-growing startups to tech leaders like Google and Stripe, to turn bold ideas into products with the power to transform the world. The role is open to candidates based in Portugal preferably in Lisbon.About the roleAs an AI Engineer at Fluxon, you’ll take the lead in designing, building and deploying AI-powered applications for our clients.You'll be responsible for:System Architecture: Design and implement end-to-end AI systems and their parts, including data ingestion, preprocessing, model inference, and output structuringGenerative AI Development: Build and optimize RAG (Retrieval-Augmented Generation) systems and Agentic workflows using frameworks like LangChain, LangGraph, ADK (Agent Development Kit), GenkitProduction Engineering: Deploy models to production environments (AWS/GCP/Azure) using Docker and Kubernetes, ensuring high availability and scalabilityEvaluation & Monitoring: Implement feedback loops to evaluate model performance (accuracy, hallucinations, relevance) and set up monitoring for drift in productionCollaboration: Work closely with other engineers to integrate AI endpoints into the core product and with product managers to define AI capabilitiesModel Optimization: Fine-tune open-source models (e.g., Llama, Mistral) for specific domain tasks and optimize them for latency and costYou'll work with technologies including:LanguagesPython (Preferred)Java / C++ / Scala / R / JavaScript AI / MLLangChainLangGraphGoogle ADKGenkitOpenAI APILLM - Large Language ModelVertex AICloud & InfrastructurePlatforms: Google Cloud Platform (GCP) or Amazon Web Services (AWS)Storage: Google Cloud Storage (GCS) or AWS S3Orchestration: Temporal, KubernetesData StoresPostgreSQLFirestoreMongoDBMonitoring & ObservabilityGCP Cloud Monitoring SuiteQualifications5+ years of industry experience in software engineering rolesStrong proficiency in Python or any preferred AI programming language such as Scala, Javascript and JavaStrong understanding of Transformer architectures, embeddings, and vector similarity searchExperience integrating with LLM provider APIs (OpenAI, Anthropic, Google Vertex AI)Hands-on experience with agent workflows like LangChain, LangGraphExperience with Vector Databases and traditional SQL / NoSQL databasesFamiliarity with cloud platforms, preferably GCP or AWSUnderstanding of patterns like RAG (Retrieval-Augmented Generation), few-shot prompting, and Fine-TuningSolid understanding of software development practices including version control (Git) and CI/CDNice to have:Experience with Google Cloud Platform (GCP) services, specifically Vertex AI, Firestore, and Cloud FunctionsKnowledge of prompt engineering techniques (Chain-of-Thought, ReAct, Tree of Thoughts)Experience building "Agentic" workflows where AI can execute tools or API calls autonomouslyWhat we offerExposure to high-profile SV startups and enterprise companiesCompetitive salaryFully remote work with flexible hoursFlexible paid time offProfit-sharing programHealthcareParental leave, including adoption and fosteringGym membership and tuition reimbursementHands-on career development