Senior Backend Engineer — AI-Scale & Distributed Systems

JobFluent; Barcelona; Híbrido; EUR 70.000 - 110.000; Jornada completa

Ventajas ofrecidas por este puesto de trabajo

Stock options

New office on Gran Via (Barcelona)

Flexible benefits: transport, meals, &

Health insurance

Work with founders in AI startups

Descripción de la vacante

Cala AI, based in Barcelona, seeks an experienced Backend Engineer to own end-to-end backend systems powering AI-driven verification at scale. You will develop services in Python (FastAPI), design data stores across SQL/NoSQL, and scale pipelines in a fast-moving startup.

Hybrid in Barcelona (Gran Via office, 3 days/week). Stock options and flexible benefits are offered as part of a competitive package. You’ll collaborate with a tight team building trustable AI systems with real impact.

Formación

• 4+ years hands-on backend engineering experience.

Responsabilidades

• Design and build backend services using Python (FastAPI).
• Architect data storage and retrieval systems using SQL and NoSQL technologies (Postgres, Redis, Cassandra, graph databases).
• Develop and maintain scalable pipelines (batch and streaming).
• Work with cloud infrastructure on AWS and containerized environments (Kubernetes).
• Experiment with emerging AI engineering tooling (coding agents, MCP ecosystems, etc.).
• Collaborate on system design and cross-functional architectural decisions.
• Contribute to a culture of clean, pragmatic, high-quality engineering.

Conocimientos

Python

FastAPI

Distributed systems

APIs

PostgreSQL

Redis

Cassandra

Graph databases

AWS

DevOps

Data pipelines

Descripción del empleo

Cala AI, based in Barcelona, seeks an experienced Backend Engineer to own end-to-end backend systems powering AI-driven verification at scale. You will develop services in Python (FastAPI), design data stores across SQL/NoSQL, and scale pipelines in a fast-moving startup.

Hybrid in Barcelona (Gran Via office, 3 days/week). Stock options and flexible benefits are offered as part of a competitive package. You’ll collaborate with a tight team building trustable AI systems with real impact.