Senior Backend Developer

3ap

Senior Backend Developer solving hard problems collaboratively in a fast-moving AI-driven environment. Delivering end-to-end backend solutions using Java/Spring and relevant technologies.

Posted 4/22/2026full-timeBelgrade • 🇷🇸 SerbiaSeniorWebsite

Tech Stack

Tools & technologies

AngularDockerJavaJavaScriptJenkinsKubernetesMongoDBNode.jsOpenShiftPostgresPythonReactSpringVue.js

About the role

Key responsibilities & impact

Work on separate projects but solve hard problems together
Own work end-to-end as part of the engineering team
Look for flaws in logic before production
Build guardrails and verify AI output manually

Requirements

What you’ll need

5+ years with Java/Spring
Solid REST API design and integration experience
Hands-on with Docker, Kubernetes, Jenkins, and OpenShift
Rigorous about testing, especially where AI outputs are involved
Comfortable with API tools like Postman or Insomnia
University degree in CS or equivalent
Fluent English
Useful, but not required: WebFlux / reactive programming, Node.js, PostgreSQL, MongoDB, React, Angular, or Vue, CI/CD and DevOps hands-on experience, Prompt engineering or multi-step AI workflows, Comfort and openness to working with Python, Background in insurance or finance, Any German

Benefits

Comp & perks

Work that uses current technology, including AI in production
Flexible hours, hybrid work
25 vacation days + 2 extra 3ap holidays
Private pension, private health insurance, 24/7 accident insurance
Maternity and paternity leave support
Team events and an employee referral program

ATS Keywords

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Applicant Tracking System Keywords

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Hard Skills & Tools

JavaSpringREST API designDockerKubernetesJenkinsOpenShiftWebFluxNode.jsPostgreSQL

Soft Skills

problem-solvingattention to detailrigorous testingcommunicationcollaborationopenness to feedbackadaptabilitycritical thinkingownershipfluent English