Backend Engineer – Python / FastAPI / LLM Pipelines | 100% Remote
We are looking for an experienced

Backend Engineer

to join an international technology project focused on building an intelligent platform that combines

Python backend development, APIs, LLM-based agentic workflows and large-scale data processing

.

Location:

Spain
Work model:

100% Remote
Environment:

International team
️

English:

Good professional working proficiency required

What will you be working on?
You will help build and operate the Python backend behind an AI-powered platform used to process, compare, update and evaluate complex technical content.
Your responsibilities will include:
Designing and maintaining REST APIs using

Python and FastAPI

.
Developing typed API schemas with

Pydantic

and strong typing practices.
Building asynchronous backend components and secure endpoints.
Developing agentic AI pipelines using

LangGraph and LangChain

.
Implementing workflows for content discovery, matching, editing, validation and evaluation.
Integrating

Azure OpenAI

models using structured outputs and function/tool calling.
Developing RAG-based solutions using embeddings and

FAISS

.
Implementing grounding, provenance and hallucination-control mechanisms.
Processing engineering datasets and large structured XML documents.
Performing data transformations using

pandas and openpyxl

.
Developing database integrations using

SQLAlchemy 2.x, PostgreSQL and AWS Aurora

.




Containerizing and deploying backend workloads using

Docker and AWS ECS/Fargate

.
Working with AWS services such as

ECR, Secrets Manager, RDS and SSO

.
Maintaining automated testing practices using

pytest

.

What are we looking for?
Strong professional experience with

Python

.
Solid experience developing APIs with

FastAPI

.
Experience with

Pydantic, async Python and typed backend development

.
Experience with

SQLAlchemy and PostgreSQL

.
Hands-on experience developing LLM applications using

LangGraph and/or LangChain

.
Experience integrating

OpenAI or Azure OpenAI APIs

.
Knowledge of

RAG, embeddings, vector search and structured LLM outputs

.
Experience implementing techniques to reduce hallucinations and improve LLM output quality.
Experience processing structured or semi-structured datasets.
Knowledge of

Docker and AWS cloud services

.
Experience with automated testing using

pytest

.
Experience with XML processing is highly valued.
Experience with AWS Aurora, ECS/Fargate or RDS Data API is a plus.
Good professional English communication skills.

Technology Stack
Python · FastAPI · LangGraph · LangChain · Azure OpenAI · RAG · FAISS · Pydantic · SQLAlchemy · PostgreSQL · AWS Aurora · Docker · ECS/Fargate · pandas · XML · pytest

If you enjoy working at the intersection of

backend engineering, generative AI and cloud-based data processing

, we would love to hear from you.

📌 Backend Engineer - Python / FastAPI / LLM Pipelines | 100% Remote (Madrid)
🏢 Infoser New Technologies
📍 Madrid