Senior Backend Engineer – Python & AIAbout the roleWe are looking for a Senior Backend Engineer to join an AI Engineering team within a large international technology environment.In this role, you will design, build, and operate robust Python backend services that power AI-enabled applications and reusable engineering capabilities across a complex enterprise ecosystem.This is a highly hands-on senior individual contributor position, focused on solving real production challenges, making sound architectural decisions, and turning AI and data-science capabilities into secure, reliable, scalable, and maintainable software.You will take ownership of backend services from initial design through production operation, working closely with Data Scientists, Product Managers, Platform Engineers, Security Specialists, and Architects.If you enjoy building production-grade Python services, designing APIs and distributed systems, working with AWS, and integrating AI/LLM capabilities into real-world applications, this could be a great fit.What you'll doDesign, build, and maintain scalable backend services and APIs using PythonOwn backend services end-to-end, from architecture and implementation through deployment and production operationIntegrate AI models, Large Language Models (LLMs), and Machine Learning services into production systemsDefine service boundaries, data models, persistence strategies, and integration contractsDesign resilient distributed systems with appropriate failure handling, retries, fallbacks, rate limits, and asynchronous processingWork with relational databases, data modelling, schema evolution, and persistence strategiesDeploy and operate backend services in AWS cloud environmentsDesign services with reliability, security, observability, performance, and cost in mindHandle production AI concerns such as latency, structured outputs, sensitive data, model failures, and external API limitationsImprove automated testing, CI/CD pipelines, monitoring, dashboards, logging, and alertingWork with Docker and Kubernetes to containerise and operate backend workloadsLead technical discussions, challenge weak architectural approaches,



and help reduce unnecessary complexityParticipate in code reviews and help establish strong backend engineering standardsMentor other engineers and share software engineering best practicesCollaborate closely with Data Scientists, Product Managers, Platform Engineers, Security Specialists, and ArchitectsMust HaveTypically 7+ years of experience in Backend Software Engineering, although technical depth, ownership, and impact are more important than an exact number of yearsStrong Python software engineering skillsSolid experience designing and building backend services and REST APIsStrong understanding of software architecture, service boundaries, distributed systems, and failure handlingExperience with relational databases, data modelling, and schema evolutionHands-on experience deploying and operating production services in cloud environments, ideally AWSStrong knowledge of software testing and engineering best practicesExperience with CI/CD pipelines and production deployment processesSolid understanding of observability, logging, monitoring, dashboards, and alertingExperience with Docker and KubernetesPractical understanding of security, privacy, sensitive data, and data protection principlesStrong problem-solving skills and ability to make and explain technical trade-offsExperience working effectively across engineering, product, data, platform, and architecture teamsFluent English and SpanishNice to HaveExperience with FastAPIHands-on experience with AWS services and cloud-native architecturesExperience with Amazon EKSFamiliarity with Infrastructure as Code, especially TerraformExperience with PostgreSQL, Amazon Aurora, or similar relational databasesExperience with asynchronous processing and event-driven architecturesFamiliarity with queues, messaging systems, or event-based integration patternsExperience with enterprise identity, authentication,



and authorisationExperience integrating AI, Machine Learning, or LLM capabilities into production backend systemsFamiliarity with production concerns around LLM APIs, including latency, rate limits, retries, fallbacks, structured outputs, and observabilityExperience in complex enterprise or large-scale digital environmentsHybrid model – 2 days onsite per week in Viladecans, BarcelonaWhy join this project?People first – diverse and inclusive culture in an international environment.Build production-grade backend systems that power real AI-enabled applicationsWork deeply with Python, APIs, distributed systems, databases, and cloud-native technologiesGain exposure to real-world AI and LLM integration without moving away from hands-on software engineeringWork in an AWS-based environment with modern cloud and platform engineering practicesInfluence architecture, engineering standards, reliability, observability, and production qualityTake real ownership of services and technical decisions instead of simply implementing predefined ticketsRemain hands-on while having meaningful technical influence across the teamHigh team stability and collaborative culture.€1200 per year training budget and continuous learning opportunities.Adaptable compensation model.Private health insurance and benefits package.Flexible working hours and hybrid model.Wellhub: fitness, wellness, and mental health support.Football and paddle tennis teams sponsored by Capitole.Team buildings, global events, and strong tech communities.Want to know more about us? Click here and discover all the details.Curious about our culture? Check out what people are saying about us on Glassdoor.We know that not every candidate will meet 100% of the requirements. If your profile doesn't match perfectly but you believe you can add value, we'd still love to hear from you.Ready for the challenge? Apply now!Empowering People, Unlocking Innovation.Information Security NoticeThe employee will have access to confidential information related to Capitole and the assigned project.Compliance with internal security and information protection policies is mandatory.

📌 Senior Python Backend Engineer (Barcelona)
🏢 Capitole
📍 Barcelona