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. ⚡ Versátil 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.

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