Senior Backend Engineer – Python & AI
About the role
We 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 do
Design, build, and maintain scalable backend services and APIs using Python
Own backend services end-to-end, from architecture and implementation through deployment and production operation
Integrate AI models , Large Language Models (LLMs) , and Machine Learning services into production systems
Define service boundaries , data models , persistence strategies , and integration contracts
Design resilient distributed systems with appropriate failure handling , retries , fallbacks , rate limits , and asynchronous processing
Work with relational databases , data modelling , schema evolution , and persistence strategies
Deploy and operate backend services in AWS cloud environments
Design services with reliability , security , observability , performance , and cost in mind
Handle production AI concerns such as latency , structured outputs , sensitive data , model failures , and external API limitations
Improve automated testing , CI/CD pipelines , monitoring , dashboards , logging , and alerting
Work with Docker and Kubernetes to containerise and operate backend workloads
Lead technical discussions, challenge weak architectural approaches , and help reduce unnecessary complexity
Participate in code reviews and help establish strong backend engineering standards
Mentor other engineers and share software engineering best practices
Collaborate closely with Data Scientists, Product Managers, Platform Engineers, Security Specialists, and Architects
Must Have
Typically 7+ years of experience in Backend Software Engineering , although technical depth , ownership , and impact are more important than an exact number of years
Strong Python software engineering skills
Solid experience designing and building backend services and REST APIs
Strong understanding of software architecture , service boundaries , distributed systems , and failure handling
Experience with relational databases , data modelling , and schema evolution
Hands-on experience deploying and operating production services in cloud environments , ideally AWS
Strong knowledge of software testing and engineering best practices
Experience with CI/CD pipelines and production deployment processes
Solid understanding of observability , logging , monitoring , dashboards , and alerting
Experience with Docker and Kubernetes
Practical understanding of security , privacy , sensitive data , and data protection principles
Strong problem-solving skills and ability to make and explain technical trade-offs
Experience working effectively across engineering, product, data, platform, and architecture teams
Fluent English and Spanish
Nice to Have
Experience with FastAPI
Hands-on experience with AWS services and cloud-native architectures
Experience with Amazon EKS
Familiarity with Infrastructure as Code , especially Terraform
Experience with PostgreSQL , Amazon Aurora , or similar relational databases
Experience with asynchronous processing and event-driven architectures
Familiarity with queues , messaging systems , or event-based integration patterns
Experience with enterprise identity , authentication , and authorisation
Experience integrating AI , Machine Learning , or LLM capabilities into production backend systems
Familiarity with production concerns around LLM APIs , including latency , rate limits , retries , fallbacks , structured outputs , and observability
Experience in complex enterprise or large-scale digital environments
Hybrid model – 2 days onsite per week in Viladecans, Barcelona
Why join this project?
People first – diverse and inclusive culture in an international environment.
Build production-grade backend systems that power real AI-enabled applications
Work deeply with Python , APIs , distributed systems , databases , and cloud-native technologies
Gain exposure to real-world AI and LLM integration without moving away from hands-on software engineering
Work in an AWS-based environment with modern cloud and platform engineering practices
Influence architecture , engineering standards , reliability , observability , and production quality
Take real ownership of services and technical decisions instead of simply implementing predefined tickets
Remain hands-on while having meaningful technical influence across the team
High team stability and collaborative culture.
€1200 per year training budget and continuous learning opportunities.
Flexible 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 Notice
The employee will have access to confidential information related to Capitole and the assigned project.
Compliance with internal security and information protection policies is mandatory.
Sign in
To continue your applicationor continue with email
By continuing you agree to our Terms & Privacy Policy.
