Senior Python Developer

About us

Uprise is a Zagreb-based company specializing in providing digital transformation services tailored to the evolving demands of Industry 5.0, with the vision of becoming a digital age protagonist. The company is highly regarded for its specialized work in the energy, mining, public, fintech, civil and healthcare sectors. With development of software solutions that integrate advanced technologies such as mathematical optimization, AI and robotics, Uprise follows Industry 5.0 principles, shifting the focus from automation to human-centered collaboration. Our quality of service led to the fact that we are featured on the Financial Times and Deloitte lists of the fastest growing companies in Europe.

We are a leader in energy transition, using optimization and machine learning to facilitate the green economy. Our offices are located right in the center of Zagreb, where a young team of hard-working and enthusiastic experts drives our mission forward.

We are big supporters of proactiveness and are always open to supporting innovative ideas. If you're interested in end-to-end development and want to work with cutting-edge technologies, come on board 🚀

Your responsibilities

As a Senior Python Developer, you will work on the development of advanced backend systems supporting our key products and clients across various industries. Your work will have a direct impact on our customers' operations, including work on production-grade platforms in the domains of energy, optimization, and algorithmic decision-making.

Your main tasks:

• Develop and maintain a Python backend (Flask or comparable frameworks) serving modern frontend applications (React/TypeScript)
• Develop and evolve REST and JSON-RPC APIs
• Work with PostgreSQL via SQLAlchemy 2.0 and Alembic migrations
• Implement and enforce authentication, authorization, and multi-tenant data access
• Maintain consistent API behavior, error handling, OpenAPI specifications, and response formats
• Integrate backend services with optimization logic and external systems (e.g. MQTT, message queues)
• Develop algorithms for automated processes and integration with external systems
• Design and implement concurrent and multithreaded backend components to handle parallel workloads, background processing, and real-time data flows efficiently
• Write and maintain automated test suites
• Improve code quality, test coverage, and reliability of an existing production codebase
• Participate in architectural decisions and incremental refactoring where it adds clear value
• Plan tasks and activities with the Project Manager and teammates
• Collaborate with the Project Lead and other developers
• Engage in regular professional development programs

Requirements

• 3+ years of experience as a backend developer
• Master's degree in Computer Science, Mathematics, Statistics, or a related field (or equivalent work experience)
• Strong proficiency in Python and backend system design, with consistent use of type annotations
• Solid experience with Flask or comparable Python web frameworks
• Deep understanding of relational databases, especially PostgreSQL
• Familiarity with ORMs (SQLAlchemy or equivalent) and database migrations
• Proven experience designing and maintaining production APIs
• Solid understanding of concurrency and multithreading in Python (threading, asyncio, multiprocessing), including awareness of the GIL and when to apply each approach
• Ability to work confidently in an existing, non-greenfield codebase
• Experience with version control in Git/GitLab
• Good knowledge of data structure design and SQL database management systems
• Excellent command of English (Croatian is a plus)
• Pragmatic mindset with a focus on maintainability, clarity, and impact
• Team player, proactive, thoughtful, and efficient problem solver
• Ability to perform independently or in a small team

Nice to have

• Experience within the energy sector
• Familiarity with algorithm-driven backends and mathematical optimization
• Experience with JSON-RPC or non-trivial API contracts
• Knowledge of Docker and orchestration systems
• Exposure to message-based systems (MQTT, queues, background jobs)
• Familiarity with frontend technologies (React, TypeScript, HTML, CSS)
• Passion for experimenting with new technologies from the frontend, backend, and ML ecosystem
• Comfort making architectural trade-offs under real-world constraints

Why choose Uprise?

• Meaningful impact – Your work directly supports real operations and business outcomes for our clients
• Professional development – Challenging tasks, opportunity to work on different projects and to express and implement your own ideas
• Growth – Opportunity to influence architecture and long-term technical direction
• Culture – Team spirit, passion, creativity, flexibility, and proactiveness are the drivers of our company
• Salary & Perks – Competitive salary, flexible working hours, team buildings, after-work gatherings, and sports activities