Senior Backend Engineer (Python / FastAPI / Azure OpenAI)

About the Position

We’re building a brand-new engineering team focused on developing the reusable services, intelligent workflows, and AI-powered foundations that will support the next generation of Agentic AI solutions.

If you enjoy building scalable backend systems, solving complex engineering challenges, and working with modern AI technologies from day one, we’d love to meet you.

What you’ll be building

As a Senior Backend Engineer, you’ll play a key role in designing and developing strategic backend microservices that power intelligent AI solutions.

The first delivery is an Agentic Email Orchestration Service-an AI-powered microservice that orchestrates email workflows using Azure OpenAI while integrating with Microsoft 365 through Microsoft Graph API.

Beyond that, you’ll contribute to a growing ecosystem of reusable backend services supporting Agentic Case Management and future AI-driven products.

This is a greenfield environment where engineering decisions matter, ownership is encouraged, and you’ll help shape the architecture from the beginning.

Responsibilities

• Design and develop scalable backend microservices using Python and FastAPI.
• Build reusable services supporting Agentic AI capabilities.
• Integrate Azure OpenAI services into production-ready applications.
• Develop secure APIs and backend components running on Azure.
• Collaborate with architects and engineers to define scalable service boundaries.
• Design clean, maintainable, and testable backend solutions.
• Contribute to technical discussions, estimations, and architecture decisions.
• Deliver high-quality software in short iterative delivery cycles.
• Continuously improve engineering practices through automation and AI-assisted development.

Requirements

Required

• Strong experience with Python.
• Solid experience building REST APIs using FastAPI.
• Experience designing and developing microservices.
• Experience with Microsoft Azure.
• Hands-on experience with Azure OpenAI or other LLM platforms.
• Good understanding of API design and distributed systems.
• Experience working with APIM.
• Experience with Git and CI/CD.
• Strong software engineering mindset.
• Excellent communication skills in English.

Nice to Have

• Microsoft Graph API.
• Exchange Online integrations.
• Event-driven architecture.
• AI Agents.
• Prompt Engineering.
• Retrieval-Augmented Generation (RAG).
• Semantic Kernel or LangChain.
• Docker & Kubernetes.
• Infrastructure as Code.
• Experience working with enterprise-scale Azure environments.

Our engineering culture

We believe great engineers don’t just write code. They design systems. They solve problems. They continuously learn. They embrace modern AI tooling to increase quality, speed, and impact.

You’ll be encouraged to leverage tools such as Cursor, Claude Code, OpenAI Codex, and other GenAI-assisted development environments-not as shortcuts, but as engineering accelerators while maintaining full ownership of the delivered solution.

Why join this team?

Because you’ll have the opportunity to:

• Join a brand-new engineering team from day one.
• Shape the architecture-not just implement it.
• Build reusable AI services used across multiple solutions.
• Work with Azure OpenAI and modern AI technologies.
• Deliver meaningful products instead of maintaining legacy systems.
• Collaborate with highly experienced engineers.
• Influence technical direction and engineering standards.

We Offer

• Competitive compensation packages
• Flexible working hours
• Job rotation
• Learning through Arnia Academy
• Attractive projects
• Trainings
• International work experience
• Referral program
• Medical benefits

About the Company

At Arnia, we are a diverse and passionate team of software development engineers, quality assurance engineers, business analysts, system administrators, and managers, united by our shared dedication to creating high-quality software solutions and delivering exceptional services to our valued customers and partners.

We believe in customer satisfaction as being the single most important goal we want to achieve in everything we do. But we also believe that we can reach this goal while having fun at work, making friends, and enjoying working together. We have game evenings, nights out, and team building events to help us know each other better and spend quality time together. Also, we have a flat organization, with no unnecessary hierarchies and where you reach the management easily.

In Arnia you will meet very skilled software engineers with rich academic backgrounds, with passion for innovation and continuous education, self-driven and oriented toward results. At the same time, they are people with high sense of humour, fun and informal, that value friendship, trust and a nice working environment.

Excellence is achieved step by step, it is a journey we always take together as a team and as a modern organization.

We recognize the value of each individual, we value diversity and we support your development career – your success is our success! We take pride in helping our people to develop their career, continuously improving their skills and their technical knowledge and to fully reach their own development goals.

People are different, they are coming from various cultures and are motivated by different things:

• The financial interests
• The career development plan
• The technologies and the projects
• The work-life balance
• The opportunities to travel abroad

Why Arnia?

We recognize people’s diversity and we try to meet everyone’s goals.

• Game Evenings
• Nights Out
• Team Buildings
• Trainings

Arnia encourages you to pursue your own interests, projects and ideas – passion can turn small things into big things – we want to be part of your own individual success. Let us know your ideas and your personal interests and we will find a way to support you.

Relocation Package

Competitive Compensation Packages

Flexible Working Hours

Job Rotation

Performance Bonuses

Medical Benefits

Not the least, we have class A offices, located in Piata Victoriei – Europa House building, next to the metro stations and to other transportation means. It is very easy to get to work and you will enjoy the quality and the lifestyle of our offices.

Attractive Projects

International Work Experience

Referral Program

Learning Through Arnia Academy

And if you like all these, why don’t you join us?