New offer - be the first one to apply!

May 27, 2026

Senior Fullstack Engineer – React and Kotlin Specialists

Senior • Remote

18,480 - 21,840 PLN

Warsaw, Poland

Unleash innovation — design the future of intelligent advertising ecosystems!
Warszawa-based opportunity with hybrid work model.

As a Senior Fullstack Engineer – React and Kotlin Specialists, you will be working for our client, a leader in building advanced advertising tools, focusing on creating intelligent recommendation systems and automating campaign management for advertisers on Allegro Ads. Join a mission-driven project that revolutionizes how businesses grow through cutting-edge technology and data-driven insights, offering exciting avenues for professional growth and innovation.

Your main responsibilities:

  • Develop and maintain backend services using Kotlin, integrating machine learning-driven recommendation engines in collaboration with data science teams.
  • Build scalable, event-driven architectures to process large data volumes within cloud environments, leveraging GCP.
  • Design and implement high-performance APIs to support analytical dashboards and market benchmarks.
  • Create and optimize scalable microfrontends using React, prioritizing accessibility and server-side rendering for analytical tools.
  • Collaborate with cross-functional teams to deliver seamless, secure, and efficient software solutions.
  • Ensure high code quality through testing frameworks such as Jest, Vitest, or Playwright, with a focus on performance and reliability.
  • Contribute to evolving microservice architectures, utilizing Spring Boot, MongoDB, SQL, and cloud-native tools.
  • Participate actively in code reviews, sprint planning, and technical discussions to foster continuous improvement.

You're ideal for this role if you have:

  • At least 3 years of experience in full-stack development, with a focus on React and Kotlin.
  • Strong proficiency in TypeScript, React, HTML/CSS, and backend technologies like Kotlin, Spring Boot, and microservices.
  • Experience working with cloud ecosystems, preferably GCP.
  • Solid understanding of database management, including MongoDB and SQL.
  • Familiarity with event-driven architectures and large-scale data processing.
  • Ability to communicate effectively in Polish and English.
  • Experience working in an Agile environment with a focus on delivering high-quality software.

It is a strong plus if you have: (optional)

  • Certifications related to GCP or microservices architecture.
  • Experience with agentic coding tools like Copilot/OpenCode.
  • Knowledge of accessibility standards (a11y) and performance optimization techniques.

Language Required for the role:

  • Polish (Communicative)
  • English (Communicative)

Eligibility for this role:

  • Only candidates with an existing legal right to work in the European Union will be considered for this role.

#MAKEYourCareerBETTER
Interested? Apply now and include your CV (preferably in English) along with a statement confirming your consent to the processing and storage of your personal data.