Senior Software Engineer

KUBO; Wrocław; Hybrid; PLN 251,000 - 312,000; Full time

Benefits offered by this job

MultiSport card

Job summary

KUBO is seeking a Senior Python Developer to scale a platform for smartwatches and tablets used by retail and hospitality across Europe. You will build backend features in Python, improve reliability, and work on MQTT-enabled communications with a hybrid office presence in Wrocław.

The role emphasizes hands-on engineering, code quality, and collaboration with the Tech Lead and Android team.

Qualifications

• 4-5+ years of backend development experience.
• Design and build distributed, scalable backend services.
• Strong Python skills with FastAPI, Django or Flask.
• Experience with relational (MySQL) and non-relational (Redis) databases.
• Solid MQTT knowledge (QoS, retained messages, broker config).
• Networking basics: TCP/IP, routing, load balancing.
• Experience with Docker and Git.
• Cloud experience (AWS/GCP/Azure).
• English at least B2; hybrid working in Wroclaw.

Responsibilities

• Build and develop backend features in Python.
• Improve performance and reliability of services for devices and mobile communications.
• Investigate connectivity issues and ensure stable device communication.
• Maintain communication layer between devices and backend services.
• Develop integrations with external customer systems.
• Work with MQTT and broker configuration.
• Write clean code, implement automated tests, and participate in code reviews.
• Collaborate with Tech Lead and Android team on product decisions.
• Contribute to backend architecture as platform scales.

Skills

Python backend

Distributed systems

English B2

Backend services

Code quality & testing

Education

Technical university degree in Computer Science or related field

Tools

FastAPI

Django

Flask

MySQL

Redis

MQTT brokers (Mosquitto/HiveMQ/EMQX)

Docker

Git

AWS/GCP/Azure

Job description

We are looking for a Senior Python Developer to help scale a growing platform for smartwatches and tablets used by retail and hospitality businesses across Europe.

The company provides devices and subscription-based infrastructure for a connected-device ecosystem. As the number of devices, customers and integrations grows, we need to strengthen the backend that supports reliable communication between devices and services.

This is a deeply technical, hands-on role. You will build and improve backend services, solve connectivity issues and work closely with the Tech Lead and Android team.

The team is working in hybrid model of work: 2-3 days from the office in Wrocław.

Key responsibilities

• Build and develop backend features in Python.
• Improve the performance and reliability of services that support smartwatches, tablets and mobile communication.
• Investigate and fix connectivity issues, including delays, unstable device connections and TCP disconnects.
• Maintain and develop the communication layer between devices and backend services.
• Build and support integrations with external customer systems.
• Work with MQTT communication, including QoS settings, retained messages and broker configuration.
• Write clean, maintainable code and follow good engineering practices.
• Take part in code reviews and write automated tests to maintain strong code quality.
• Work closely with the Tech Lead and Android Developers on product and technical decisions.
• Help improve backend architecture as the platform, number of devices and customer integrations grow.

Ideal candidate profile

• At least 4-5 years of commercial experience in backend development.
• Proven experience designing and building distributed systems, cloud-based applications or scalable backend services.
• Strong Python skills and hands-on experience with FastAPI, Django, Flask or a similar framework.
• Experience working with relational databases, especially MySQL, and non-relational databases, especially Redis.
• Good knowledge of MQTT, including QoS, retained messages and broker configuration with tools such as Mosquitto, HiveMQ or EMQX. MQTT configuration matters in connected-device systems because QoS defines message-delivery behaviour, while retained messages allow a broker to provide the most recent value for a topic to clients that subscribe later
• Solid understanding of networking concepts, including TCP/IP, routing and load balancing.
• Experience with Docker and Git.
• Experience working in a cloud environment: AWS, GCP or Azure.
• Strong focus on clean code, automated testing, code quality and maintainable solutions.
• Technical university degree in Computer Science, Software Engineering or a related field.
• English at minimum B2 level, allowing comfortable day-to-day communication.
• Openness to hybrid work from the office (2-3 days per week) - it is important because the whole team is based in Wrocław.

Conditions

• Work model: hybrid in Wrocław (2-3 days per week)
• Employment type: B2B or Contract of employment - it is up to you! You will be hired directly by customer, it is not outsourcing model.
• Salary: for B2B: 22 500 - 28 000 net/month, for Contract of employment: 18 000 - 23 000 PLN gross/month
• Benefits: MultiSport card.

Recruitment steps

• Phone call or online meeting with Recruiter from KUBO - 30 minutes.
• Technical interview - a 1.5-hour Microsoft Teams interview with the Tech Lead from the team.
• Final stage - a 1.5-hour in-person interview with the CEO in the office in Wrocław.
• Decision and feedback.