Senior Full Stack Developer

Onthespotdev; Warszawa; On-site; PLN 60,000 - 90,000; Full time

Job summary

Onthespotdev is looking for a Senior Python Engineer located in Warsaw, Poland. In this role, you will be responsible for building and maintaining robust backend services within an existing application, ensuring code quality, stability, and maintainability.

The ideal candidate will have over 5 years of experience in Python development, primarily with FastAPI and PostgreSQL. Additional skills in Docker and Kubernetes are preferred.

This position offers support in a positive work environment with opportunities for growth and development.

Qualifications

• 5+ years of experience in development with Python.
• Experience in designing, developing, and maintaining backend services.
• Proficient in working with relational databases and writing efficient code.

Responsibilities

• Build and maintain robust backend services for a startup.
• Write clean, scalable Python code with a focus on testing.
• Diagnose and resolve complex backend and production issues.

Skills

Python

FastAPI

PostgreSQL

Docker

Kubernetes

Celery

Agile methodologies

Tools

GitHub

OpenTelemetry

Job description

We bring startups and disruptive tech companies to the local market, offering engineers the opportunity to work on innovative, high-impact products. Join us and become a member of their R&D team while we take care of employment, HR support, a benefits package, and an enjoyable work environment.

AITHENA is a startup focused on creating an AI-powered tool to enhance the regulatory review process in the pharmaceutical industry.

Our goal is to build an AI-powered assistant for document analysis and review related to pharmaceutical regulations, enabling efficient search and user query responses based on a comprehensive database of legal case documents.

About the role

We are seeking a Senior Python Engineer to build and maintain robust backend services within an existing application.

Responsibilities

• Write clean, concise, and scalable Python code, ensuring stability, maintainability, and proper unit testing.
• Implement new requirements in an Agile environment, following architectural principles and engineering standards.
• Diagnose complex backend and production issues, using monitoring, telemetry, and logging tools to evaluate options and implement effective solutions.
• Work on performance optimization, testing, troubleshooting, and improving backend service reliability.
• Work with Dockerized backend services and participate in CI/CD processes using GitHub Actions.
• Have a basic understanding of Kubernetes, Argo CD, and Helm Charts to support troubleshooting of backend service deployments when needed.
• Apply basic networking and infrastructure knowledge to investigate backend service issues in Azure-based environments.
• Contribute to architecture and design discussions, ensuring solutions follow best practices.

Requirements

• 5+ years of experience in development with Python.
• Design, develop, and maintain backend services using Python and FastAPI.
• Write clean, efficient, and testable code for scalable systems.
• Integrate and work with relational databases, primarily PostgreSQL.
• Implement background processing and task queues using Celery.
• Diagnose and resolve complex technical issues in backend systems (including cloud environments like Azure).
• Collaborate with the team on architecture, code reviews, and problem-solving (using GitHub for version control).
• Participate in performance optimization and testing (e.g., with Pytest).
• Apply knowledge of infrastructure and monitoring tools (e.g., Docker, Kubernetes, OpenTelemetry, Argocd) to support backend reliability.
• Proactively learn and adopt new technologies relevant to backend development and cloud operations.

Nice to have

• Basic front-end experience with React
• Experience with LLM frameworks (LlamaIndex or LangChain)

At On The Spot, we’re creating a workplace people would want to stay in: supportive, well-organized, and fair in terms of conditions and benefits.

We’ll share more about our benefit package during the interviews. In the meantime, you can always check our Glassdoor reviews.

Position is open to candidates in Poland. You need to have a residence permit or another valid document allowing work in Poland. Thank you!