Senior Python Backend Engineer

Capitole; Barcelona; Híbrido; EUR 70.000 - 90.000; Jornada completa

Ventajas ofrecidas por este puesto de trabajo

Hybrid model – 2 days onsite in Vilade

Private health insurance

Annual training budget €1200

Team buildings and events

Descripción de la vacante

Capitole in Viladecans, Barcelona, seeks a Senior Backend Engineer to design, build, and operate Python backend services powering AI-enabled applications in a hybrid model. You will own backend services end-to-end, from architecture through production, and collaborate with data scientists, product managers, platform engineers, security specialists, and architects.

The role emphasizes production-grade Python APIs, distributed systems, and cloud-native practices with AWS, Docker, Kubernetes, and

Formación

• Senior backend engineer with strong Python experience in production systems.
• Hands-on ownership from design to deployment and operation.
• Experience building reliable, scalable backend services and APIs.
• Proficient in AWS, Docker, Kubernetes, CI/CD, and observability.
• Familiar with AI/LLM integration, data protection, and security best practices.
• Fluent in English and Spanish with strong communication skills.
• 7+ years of backend software engineering experience.

Responsabilidades

• Design, build, and maintain scalable backend services and APIs using Python.
• Own backend services end-to-end from architecture to production operation.
• Integrate AI models and LLM capabilities into production systems.
• Define service boundaries, data models, persistence strategies, and contracts.
• Design distributed systems with failure handling, retries, and timeouts.
• Work with relational databases, data modelling, and schema evolution.
• Deploy and operate backend services in AWS cloud environments.
• Ensure reliability, security, observability, performance, and cost discipline.
• Improve CI/CD pipelines, monitoring, dashboards, logging, and alerting.
• Collaborate with Data Scientists, Product Managers, Platform Engineers, Security Specialists, and Architects.

Conocimientos

Python

Backend services

APIs

Distributed systems

AWS

Docker

Kubernetes

AI/LLM integration

PostgreSQL

Security

CI/CD

Observability

Terraform

FastAPI

English

Spanish

Herramientas

AWS

Docker

Kubernetes

Terraform

PostgreSQL

Descripción del empleo

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
• Typically 7+ years of experience in Backend Software Engineering, although technical depth, ownership, and impact are more important than an exact number of years
• 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
• 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.

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.

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.