Junior Software Developer (Backend & AI)

Tenvalleys; Warszawa; Hybrid; PLN 90,000 - 130,000; Full time

Benefits offered by this job

Flexible working hours

Remote work opportunities

Licenses for advanced AI tools

Dynamic, supportive team

Job summary

Tenvalleys in Warsaw is seeking a motivated junior backend engineer. You will build backend services and REST APIs in Python or Java with Spring Boot, work with SQL databases, and integrate external systems, shipping features that call language model APIs in production with senior engineers reviewing your code.

You will write tests, participate in code reviews, keep documentation current, and use Git with CI/CD pipelines to deploy to production.

Qualifications

• 0–2 years of commercial experience or internships, studies, courses or projects.
• Working knowledge of Python and/or Java with Spring Boot.
• Backend APIs you have built, including academic or personal projects.
• Fundamentals of SQL databases; NoSQL is a plus.
• Understanding of API layering and communication through APIs.
• Git familiarity; CI/CD knowledge welcomed (GitHub Actions/Jenkins).
• Readable code with a drive to grow in testing, reviews and docs.
• Initial experience with AI: integration with a language model API.

Responsibilities

• Build and maintain backend services and REST APIs in Python or Java with Spring Boot.
• Work with SQL databases and integrate external systems and APIs.
• Ship features that call language model APIs into production.
• Write tests, participate in code reviews and keep documentation current.
• Use Git and CI/CD pipelines to get work into production.
• Learn new domains and technologies alongside analysts, testers, and DevOps.

Skills

Python

Java

Spring Boot

REST APIs

Git

CI/CD

Testing

Code review

Documentation

Teamwork

AI basics

Tools

Docker

GitHub Actions

Jenkins

Job description

Start your engineering career on real client systems. You will build backend services and REST APIs, work with databases and integrations, and ship features that use language models in production, with senior engineers reviewing your code and AI in the room from day one.

What you will do:

• Build and maintain backend services and REST APIs in Python or Java with Spring Boot
• Work with SQL databases and integrate external systems, APIs and services
• Ship features that call language model APIs, from prototype to something clients rely on
• Write tests, take part in code review and keep documentation current
• Use Git and our CI/CD pipelines to get your work into production
• Learn new domains and technologies alongside analysts, testers and DevOps engineers

What you bring:

• 0-2 years of commercial experience, or skills built through internships, studies, courses or your own projects
• Working knowledge of Python and/or Java with Spring Boot
• Backend applications or REST APIs you have built, including academic or personal projects
• Fundamentals of SQL databases; NoSQL is a plus
• An understanding of how applications are structured: layering, separation of logic and communication through APIs
• Comfort with Git; familiarity with CI/CD, GitHub Actions, Jenkins or Gitflow is welcome
• Attention to readable code and an appetite to grow in testing, code review and documentation
• First experience with AI: an integration with a language model API such as OpenAI, or a simple app, prototype or project built on AI
• A grasp of what AI and LLMs can and cannot do; no model training experience required
• Basic knowledge of system, API or third-party service integration
• An ability to work in a team, take feedback and ask questions

Nice to have: Docker, application deployment or cloud services.

You do not need to tick every box. We are looking above all for solid fundamentals, technical curiosity and the drive to grow.

What we offer:

• Flexible working hours and remote work opportunities
• Licenses for advanced AI tools so you can do cutting-edge work
• A dynamic, supportive team that has delivered together for years
• Real professional growth on enterprise-scale projects