Senior Backend Engineer - Python & FastAPI (Remote)

IO; West of England; Remote; GBP 58,000 - 90,000; Full time

Job summary

IO in the United Kingdom is seeking an experienced Senior Backend Developer to design scalable backend services using Python and FastAPI. You will build RESTful APIs and microservices, and develop data pipelines supporting large-scale analytics.

Join an international engineering programme, work remotely for a contract starting September 2026 through December 2026 with potential extension. You will collaborate with cross-functional teams, apply Domain-Driven Design, and ensure secure, well-tested

Qualifications

• Strong commercial experience with Python.
• We need production experience with FastAPI.
• A solid understanding of REST APIs and microservice architectures.
• Experience applying Domain-Driven Design (DDD).
• Strong SQL skills with PostgreSQL and/or SQL Server.
• Hands-on experience with Neo4j graph databases.
• Experience working with Docker and Kubernetes.
• Knowledge of CI/CD pipelines and Git.
• Understanding of secure software development principles.
• Excellent communication skills and experience working within Agile teams.
• Applicants must be citizens of a NATO member country and currently reside within a NATO member country.

Responsibilities

• Design and develop scalable backend services using Python and FastAPI.
• We build RESTful APIs and microservices.
• We develop data pipelines supporting large-scale analytics platforms.
• We work with Neo4j graph databases and relational databases such as PostgreSQL or SQL Server.
• We collaborate with cross-functional engineering teams to design clean, maintainable software using Domain-Driven Design (DDD).
• We write high-quality, well-tested code and contribute to code reviews.
• We support CI/CD pipelines, containerised deployments and cloud-native development.
• We troubleshoot performance issues and contribute to architectural decisions.
• We take ownership of features from design through deployment.

Skills

Python

DDD

REST APIs

Microservices

Agile teamwork

Security best practices

Tools

FastAPI

Docker

Kubernetes

PostgreSQL

SQL Server

Neo4j

Git

CI/CD

Azure

Databricks

Grafana

Kafka

Job description

IO in the United Kingdom is seeking an experienced Senior Backend Developer to design scalable backend services using Python and FastAPI. You will build RESTful APIs and microservices, and develop data pipelines supporting large-scale analytics.

Join an international engineering programme, work remotely for a contract starting September 2026 through December 2026 with potential extension. You will collaborate with cross-functional teams, apply Domain-Driven Design, and ensure secure, well-tested