We are hiring a Senior Software Engineer for a fixed-term contract ending in June 2026, based in Barcelona or Zaragoza with a hybrid working model. This role is with a leading European deep-tech company working at the intersection of AI, machine learning, and advanced computing. You will collaborate with world-class engineers and researchers to industrialize cutting-edge technologies and deliver solutions to large enterprise and public-sector customers. Por favor, lea detenidamente la información de esta oferta de empleo para entender exactamente qué se espera de los posibles candidatos.What is offered: Competitive annual salary, depending on experience and qualifications Signing bonus upon joining and a retention bonus at contract completion Relocation support if applicable Fixed-term contract until June 2026 Hybrid working model with flexible hours International, highly technical environment within a fast-scaling Series B company Role responsibilities: Develop, deploy, and maintain production-grade software systems across frontend and backend Work closely with software, DevOps, ML, and research teams to industrialize core technologies Contribute to high-impact projects for large enterprise and government customers Take ownership of system design, APIs, and application workflows Maintain high engineering standards through testing, documentation, and clean code practices Required experience: Bachelor’s degree or higher in Computer Science, Engineering, or equivalent industry experience Strong expertise in Python; additional experience with Rust or C/C++ is a plus Experience level aligned with junior (1–2 years), mid (3+ years), or senior (5+ years) profiles Experience in frontend and backend development Proficiency with TypeScript and frameworks such as Flask or FastAPI xsgfvud Experience deploying software in cloud environments such as AWS Strong knowledge of Git and CI/CD pipelines Excellent communication skills and ability to collaborate across disciplines Preferred experience: Hands-on experience working with LLMs and related tools (HuggingFace, OpenAI APIs, vector databases) Experience with distributed systems or frameworks such as Ray or Spark Experience working in cross-functional teams and designing scalable software architectures This is a fixed-term contract role ending in June 2026.