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July 16, 2026

Staff Backend Engineer - JVM (Java/Kotlin) & AWS

Senior • Remote

7,500 - 8,300 EUR/yr

Berlin, Germany

Intro

At Adsquare, our mission is driven by our core focus: Passion, solving complex challenges with great people, tech, and data; and Niche, location intelligence for programmatic advertisers.

Our core values are integral to everything we do:

  • Drive: We turn ambition into action.
  • Resilience: We adapt, persevere, and grow stronger.
  • No BS: We value honesty, transparency, and clear communication.
  • Humble: We choose modesty over vanity and let results speak for themselves.
  • Moral Compass: We do the right thing with fairness, integrity, and respect.

We seek candidates who not only bring excellent technical expertise but also embody these values in every aspect of their work.

Your Mission

As a Staff Backend Engineer, you will own the design and operation of the high-throughput JVM services that turn massive streams of location data into products our partners depend on in real time.

You will operate with a high degree of autonomy and engagement, seeking out the problems worth solving, driving performance and reliability across our services, and making the architectural decisions that shape how the whole organisation builds and scales.

You will thrive in ambiguity, turn business-critical challenges into systems that hold up under real-world load, and lift the engineers around you as you go.

Key Responsibilities

  • Design and evolve distributed backend systems with a strong focus on scalability and correctness.
  • Take services from architecture decisions through deployment and day-to-day operation.
  • Maintain existing partner integrations and build new ones to deliver large-scale data to our partners reliably.
  • Build and operate cloud-native systems on AWS, including migrating services from monolithic to cloud-native architectures.
  • Monitor system health, troubleshoot production issues, and optimise for performance, memory, and latency.
  • Collaborate closely with Product and Data teams to deliver features that move the business.
  • Raise the engineering bar across teams: drive cross-team architecture decisions and grow the engineers around you.

Your Profile

We are looking for a staff-level engineer with a strong backend and cloud background who is comfortable owning complex systems in production.

Our stack is centered on Java, Kotlin, and AWS, and while the specifics are listed below, we don't expect prior experience with every tool we use.

Must-Have Skills

  • 8+ years building backend systems in production, with a track record of owning services end to end.
  • Experience mentoring senior engineers and influencing technical direction across teams.
  • Strong expertise in Java or another JVM language (Kotlin, Scala) and the Spring ecosystem.
  • Proven experience designing and operating distributed systems under real-world load.
  • Deep, hands-on AWS experience (for example S3, SQS/SNS, Lambda, IAM), including designing cloud-native architectures.
  • Hands-on experience with Docker and containerised deployment workflows.
  • Practical experience building and maintaining CI/CD pipelines (for example GitHub Actions, GitLab CI, Jenkins).
  • Fluency with AI-assisted development tools (for example Copilot, Cursor, Claude Code), using them to accelerate design, coding, testing, and review while keeping strong judgment over correctness, security, and maintainability.
  • A strong understanding of concurrency, data consistency, and system reliability.
  • Experience with PostgreSQL or other relational/NoSQL databases (for example MongoDB) in high-throughput environments.
  • A proactive approach: you identify problems, take ownership, and drive solutions with a high degree of autonomy.

Nice to Have

  • Experience with systems processing large data volumes or high request throughput.
  • A feel for architectural trade-offs (for example synchronous vs. asynchronous processing) and comfort making decisions with incomplete information.
  • Experience helping a team adopt AI-assisted development practices thoughtfully, balancing speed with quality.
  • Experience with our wider environment: Terraform, MongoDB, Kubernetes, and AWS data tooling (Athena, Glue, Batch, Step Functions).
  • Background in partner integrations or API-driven systems, or evolving systems from monolithic to cloud-native.

Why us?

  • We are open to flexible work models: we work in a hybrid mode and remotely from anywhere in the world up to 3 months per year.
  • You are entitled to 30 vacation days per year.
  • We offer Urban Sports Club membership and a company pension scheme.
  • Regular team events and company events organised by our People team.
  • We equip you with the latest hardware and provide you with all the tools you need to thrive.
  • Salary range: €90,000 up to €100,000 per year depending on experience.

Recruiting Process

  • Step 1: Intro and values conversation.
  • Step 2: Technical interviews covering backend fundamentals and system design.
  • Step 3: Meet the team, followed by decision and offer.
  • Reference check conducted at the final stage.

Work model

  • Remote (can also be B2B), open across Europe.

Desired start date

  • As soon as possible.

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That means working closely with Product, AI, and Operations teams to design agentic systems, distributed data pipelines, and scalable incident response infrastructure — and doing it in a way that lets the team ship with confidence multiple times a day. WHAT YOU'LL WORK ON Architecture and feature design Partner with Product, AI, and Operations teams to architect new features and complex agentic systems. Make clear architectural trade-offs that balance platform, product, and business goals. Backend services and APIs Build and maintain the backend services and APIs that power the core product. Ensure systems are secure, well-tested, and high performance. Distributed systems Design and implement distributed services to orchestrate data pipelines, automate investigations, and enable incident response at scale. Operational excellence Own operational best practices so the team can ship multiple times a day with confidence. Healthy on-call culture and strong observability are part of what you'll build and maintain. Engineering standards Set the bar for writing, communication, and system design across the team. Your influence will shape how a modern AI-native product is built. WHAT WE LOOK FOR 5–10+ years of backend engineering experience A strong track record designing, building, and operating production backend systems at scale. Deep backend fundamentals Expertise in API design, data modelling, and reasoning about distributed systems trade-offs. You understand the nuances, not just the patterns. AWS or GCP hands-on experience Solid understanding of how infrastructure decisions impact application reliability and performance. You've run things in production, not just designed them. CI/CD in practice Practical experience with testing and deployment strategies in high-frequency shipping environments. Observability and on-call maturity A solid grasp of what good observability looks like and how to build healthy on-call practices that don't burn people out. Bonus Experience at an early-stage or scaling startup. Exposure to modern AI and ML systems. Experience shipping product without a dedicated product manager. TECH STACK TypeScript, React, Node.js, AWS, Terraform, PostgreSQL, OpenAI, Azure AI. The team uses GitHub, Slack, Linear, Figma, and Notion day to day. THE TEAM Small, senior, and in-person. The office is in central Wrocław, next to the main train station. The expectation is 4–5 days a week in the office — this is a deliberate choice, not a compromise. Relocation support is available for the right candidate. COMPENSATION & BENEFITS Salary $130,000 – $190,000 USD depending on experience, plus competitive equity. Wellness and commute stipend $100 per month. Hardware Premium hardware provided — MacBook Pro and AirPods. Food Daily in-office lunch and dinner. Time off 20 PTO days plus 9 US public holidays. Relocation Support available for candidates relocating to Wrocław.

Technology

DataArt

Senior Backend Engineer with Java

Senior

Remote

Wroclaw, Poland

16,000 - 19,000 PLN

🏢 Summary: Senior Backend Engineer role focused on defining the technical direction and architecture of a domain within a borderless financial platform. The position involves designing scalable microservices, driving architectural decisions, and leading a small backend team in a distributed environment. The role emphasizes reliability, security, and high‑volume transaction processing in a cloud-based ecosystem. 🗂️ Requirements: 4-7 years backend engineering experience, Proficiency in Go, Experience with Java 21 or modern Java, Experience designing microservices with clear contracts, Experience with caching strategies including TTL and invalidation, Experience with event-driven or asynchronous architectures, Experience with structured logging, metrics, and alerting, Experience with AWS services, Experience with relational and non-relational databases, Experience with Spring Boot or similar frameworks, Experience reviewing code and architectural decisions, Availability to work in GMT+5:30 timezone 📃 Skills: Java, Go, Spring, JDBI, PostgreSQL, CockroachDB, DynamoDB, Redis, SQS, SNS, Kafka, AWS, EKS, ALB, RDS, S3, Kong, Datadog, Quickwit, JWT, RBAC, TLS, Docker, ArgoCD, GitHub, Microservices, Kafka, CDC 🏢 Description: Project overview This project focuses on developing a borderless financial platform that supports international banking flows, payments, account management and regulatory compliant operations. The product handles sensitive data and high volume transactions while prioritising reliability and security. Team You will work in a distributed environment with backend engineers, a product manager and platform specialists. The role involves leading a sub team of three to five engineers, conducting design reviews, ensuring code quality standards and supporting collaborative decision making. Position overview We are looking for a Senior Backend Engineer who will define the technical direction of a backend domain and drive architectural decisions. You will design microservices, create scalable solutions, guide a small engineering group and collaborate closely with product specialists to shape the delivery roadmap. We are looking for a person willing to work in the time zone: GMT+5:30. Technology stack Java 21, Go, Spring Boot, JDBI, custom workflow engines, PostgreSQL, CockroachDB, DynamoDB, Redis, SQS, SNS, Kafka, AWS EKS ALB RDS S3 Secrets Manager, Kong API Gateway, Datadog, Quickwit, JWT RBAC TLS request and response encryption VAPT, GitHub Actions, Docker, ArgoCD, microservices, event driven architecture, saga and orchestration patterns, CDC pipelines, maker checker workflows Responsibilities Plan and design backend microservices with clear boundaries and contracts Develop solutions for domains such as onboarding, payments, transaction orchestration or platform components Break complex epics into actionable tasks with clear acceptance criteria Review designs from other engineers to ensure scalability and fault tolerance Drive technical decisions including caching layers, asynchronous processing strategies, database choices and API versioning Evaluate build versus buy options for integrations and services Collaborate with a product manager to align on scope and prioritisation Lead a sub team of backend engineers and support their professional growth Support incident response, root cause analysis and long term improvements Monitor service performance using logging, metrics and tracing tools Requirements Professional backend engineering experience from 4-7 years Experience with Go (tooling & CLIs) Experience designing microservices with well-defined contracts and boundaries Experience with Java 21 or modern Java versions Experience with caching strategy design, including TTL and invalidation approaches Experience working with asynchronous processing, event-driven architecture, or queue-based workflows Experience using structured logging, metrics, and alerting to debug production systems Experience in making build versus buy decisions with clear trade-off analysis Experience reviewing code and identifying architectural or contract issues Experience with AWS-based services Experience working with relational and non-relational databases such as PostgreSQL or DynamoDB Experience writing backend services using Spring Boot or similar frameworks Nice to have Experience with financial or payments related systems Experience with KYC or AML flows Experience with workflow or orchestration engines Experience with platform wide pattern creation or reusable service design Experience with data encryption practices and security audits Experience with CockroachDB or high availability distributed databases What We Offer: Vacation days : Up to 26 business days per year. 10 illness/special days off per year (fully paid, no medical papers needed) for all contract types Health and life insurance (Luxmed) MyBenefit platform with Multisport option Internal psychological support service English language classes from the first working day Access to external learning platforms : O’Reilly, LinkedIn Learning, Udemy, and a wide catalog of diverse internal training Flexible workplace : work from the office, from home, or choose a hybrid option Tech Skills Mentoring Program Opportunities to develop as a public speaker, mentor, or technical interviewer Fully paid idle (bench) when not involved in a project Certification reimbursement (AWS, GCP, Microsoft, etc.)

Technology

emagine Polska

Senior AI Software Engineer – Backend

Senior

Remote

Lisbon, Portugal

🏢 Summary: Senior AI Software Engineer – Backend role focused on designing, building, and scaling production-grade AI backend services, including LLM integrations, RAG pipelines, and distributed cloud-native systems. The position emphasizes reliable, observable, and secure AI solutions deployed in AWS using modern backend and infrastructure practices. You will work in an Agile environment delivering scalable APIs, microservices, and AI-driven workflows for enterprise use cases. 🗂️ Requirements: Bachelor’s degree in Computer Science, Software Engineering, Data Engineering, or related field, 6+ years backend or software engineering experience, Hands-on experience delivering AI-enabled or data-intensive backend solutions, Proficiency in at least one backend language: Python, Java, Go, Kotlin, C#, or TypeScript, Strong experience building REST APIs, microservices, and distributed systems, Experience with Python backend frameworks such as FastAPI and async programming, Experience integrating LLMs or cloud AI services with orchestration layers, Knowledge of RAG, vector search, and semantic retrieval concepts, Experience with SQL and NoSQL databases, Experience with AWS cloud services and cloud-native architectures, Experience with Terraform or infrastructure-as-code tools, Experience with Git and Agile/Scrum methodologies, Knowledge of testing, monitoring, logging, and AI evaluation practices 📃 Skills: Python, Java, Go, Kotlin, C#, TypeScript, FastAPI, REST, Microservices, LLM, RAG, Vector, SQL, NoSQL, AWS, Terraform, Git, Scrum, Kubernetes, Docker, CI/CD, Async, Serverless, Containers 🏢 Description: YOUR CONTRIBUTION Our culture is agile and collaborative, and we genuinely believe our people are some of the best with which you’ll ever work. We are looking for a skilled and passionate Senior AI Software Engineer – Backend to join our Centre of Excellence and the SWE team to design, build and scale production-grade AI services, intelligent workflows, and backend platforms that create measurable business value. YOUR “DAY-TO-DAY”: Design, develop and operate production-grade AI backend services, APIs, and event-driven components with strong focus on scalability, reliability, latency, and cost efficiency. Build and integrate capabilities based on LLMs and other AI services, including prompt orchestration, structured outputs, tool calling, and workflow automation. Develop retrieval and knowledge integration patterns such as RAG, vector search, and metadata-driven content pipelines for enterprise use cases. Participate and support Agile methods and frameworks by taking part in planning events, daily stand-ups, code reviews, and technical discussions. Collaborate closely with product, platform, frontend, DevOps, security, and data stakeholders as a valued member of a self-managing, cross-functional SWE team. Implement robust observability, evaluation and guardrails for AI solutions, including logging, tracing, monitoring, feedback loops and incident troubleshooting. Manage and optimize scalable distributed systems on the Cloud, using secure-by-design and infrastructure-as-code practices. Develop automated tests and evaluation suites to validate backend logic, model behavior, regression scenarios, and non-functional requirements. Translate product and business needs into reliable technical designs, reusable services, and maintainable integration patterns. Continuously improve architecture, developer experience, and engineering standards by contributing to best practices, reviews, and technical mentorship within the Backend community. BACKGROUND AND QUALIFICATIONS: Bachelor's Degree or higher in Computer Science, Software Engineering, Data Engineering, or related field, with appropriate professional experience. Proven work experience as a Backend Engineer or Software Engineer for 6+ years, with hands-on delivery of AI-enabled or data-intensive backend solutions. Strong experience with Agile delivery frameworks such as Scrum and modern source code management practices using Git. Knowledge of AI engineering patterns such as agentic workflows, semantic caching, prompt/version management, and human-in-the-loop controls. Strong proficiency in one or more backend languages such as Python, Java, Go, Kotlin, C#, or TypeScript, with production experience building APIs and services. Solid experience designing and operating backend services, microservices, and distributed systems, including RESTful APIs, asynchronous processing, and messaging patterns. Hands-on experience with Python-based AI/backend frameworks and service development patterns, such as FastAPI, async programming, data validation, and structured outputs. Experience integrating foundation model or cloud AI services and building reliable orchestration layers for prompts, tools, and model interactions. Good knowledge of data access patterns and storage technologies, including SQL and NoSQL databases, caching, and vector databases or semantic retrieval concepts. Experience with AWS cloud services and cloud-native engineering practices, including serverless, containers, observability, and infrastructure automation. Experience with Terraform or other infrastructure-as-code tooling. Knowledge of AI solution quality practices, including testing strategies, evaluation, monitoring, security, privacy, and responsible-use guardrails. Knowledgeable about software architecture, design patterns, logging, monitoring, and performance optimization. Excellent analytical and time management skills, strong teamwork mindset, and a pragmatic problem-solving attitude. Passionate about software engineering, continuous learning, and the practical adoption of emerging AI technologies. ADDITIONAL EXPERIENCE PREFERRED OR HELPFUL: Experience with cloud AI platforms and managed model services, preferably in AWS environments. Experience with Kubernetes, Docker containers, and CI/CD pipelines for deploying and operating AI-enabled services. Experience with product and collaboration tools such as Jira and Confluence. Summary: Senior AI Software Engineer – Backend Role in a nutshell: A senior backend engineer focused on building and scaling production-grade AI services — think LLM integrations, RAG pipelines, agentic workflows, and cloud infrastructure — within a collaborative, cross-functional team. Experience needed: 6+ years in backend/software engineering, with hands-on AI or data-intensive delivery. Must-have tech: Python (FastAPI, async), REST APIs, microservices, Terraform, AWS, SQL/NoSQL/vector databases, Git, Agile/Scrum. Nice to have: Kubernetes, Docker, CI/CD, Terraform, Jira/Confluence. Key soft skills: Strong communicator, team player, pragmatic problem-solver, passionate about AI and continuous learning. Degree: Computer Science, Software Engineering, or related field. The right candidate is someone who bridges solid backend engineering fundamentals with practical AI delivery experience — not just a data scientist or ML researcher, but an engineer who ships reliable, observable AI products in production.

Technology

emagine Polska

Java Backend Developer with German

Mid

Remote

180 - 200 PLN/hr

🏢 Summary: The offer is for a Backend Engineer responsible for building and maintaining high-performance backend systems in a cloud-based environment using Java, Kubernetes, and AWS. The role focuses on developing containerized applications and operating them reliably in the AWS cloud. It is a long-term remote B2B contract centered on scalable and cloud-native technologies. 🗂️ Requirements: Proficiency in Java, Experience with JVM ecosystem and Spring Boot, Experience with Kubernetes and Docker, Hands-on experience with AWS services (Lambda, EC2, ECS, EKS), Basic knowledge of Terraform, Minimum 1-2 years of AWS or other cloud platform experience, Understanding of containerization concepts, Knowledge of Camunda or AWS Step Functions 📃 Skills: Java, Python, Spring, SpringBoot, Kubernetes, Docker, AWS, Lambda, EC2, ECS, EKS, Terraform, Angular, Camunda, StepFunctions, JVM 🏢 Description: Backend Engineer (Java/Kubernetes/AWS): Introduction & Summary: This role requires a skilled Backend Engineer proficient in Java with experience in Kubernetes and AWS. The ideal candidate will be responsible for developing and maintaining efficient backend systems that prioritize performance and reliability while leveraging cloud technologies. What we offer: Full Remote Rate: 180-200 PLN/ H+ VAT Long Term B2B contract Main Responsibilities: Develop and maintain backend systems, running in Kubernetes in the AWS cloud, with a focus on performance and reliability. Build and manage containerized applications using tools like Docker and Kubernetes. Utilize cloud services, particularly AWS, to deploy and operate applications efficiently. Key Requirements: Proficiency in Java is required, with additional experience in Python as a plus. Experience with the JVM ecosystem, especially Spring Boot. Familiarity with frontend technologies, particularly Angular. Solid understanding of containerization technologies, including Docker and Kubernetes. Hands-on experience with AWS cloud services like Lambda, EC2, ECS, and EKS. Basic Terraform knowledge is essential. Minimum of 1-2 years working with AWS or equivalent experience with other cloud platforms. Knowledge of business process modeling or workflow orchestration tools such as Camunda or AWS Step Functions. Nice to Have: Experience with CI/CD pipelines. Familiarity with microservices architecture. Understanding of Agile methodologies. Other Details: This position may offer remote work flexibility. The role is for a long-term assignment focusing on cloud-based technologies in a dynamic environment.

Technology

emagine Polska

Java Backend Engineer

Mid

Remote

Warsaw, Poland

180 - 200 PLN/hr

🏢 Summary: Long-term remote B2B contract for a Backend Engineer responsible for building and maintaining high-performance backend systems in Java, deployed on Kubernetes within AWS. The role focuses on developing containerized applications and leveraging cloud services to ensure scalability and reliability. Work involves JVM-based technologies and cloud-native architecture. 🗂️ Requirements: Proficiency in Java, Experience with Spring Boot and JVM ecosystem, Hands-on experience with AWS services (Lambda, EC2, ECS, EKS), Minimum 1–2 years of experience with AWS or other cloud platforms, Strong knowledge of Docker and Kubernetes, Experience building and managing containerized applications, Basic knowledge of Terraform, Knowledge of Camunda or AWS Step Functions 📃 Skills: Java, Spring, JVM, AWS, Lambda, EC2, ECS, EKS, Kubernetes, Docker, Terraform, Camunda, StepFunctions, Angular, Python 🏢 Description: Backend Engineer (Java/Kubernetes/AWS): Introduction & Summary: This role requires a skilled Backend Engineer proficient in Java with experience in Kubernetes and AWS. The ideal candidate will be responsible for developing and maintaining efficient backend systems that prioritize performance and reliability while leveraging cloud technologies. What we offer: Full Remote Rate: 180-200 PLN/ H+ VAT Long Term B2B contract Main Responsibilities: Develop and maintain backend systems, running in Kubernetes in the AWS cloud, with a focus on performance and reliability. Build and manage containerized applications using tools like Docker and Kubernetes. Utilize cloud services, particularly AWS, to deploy and operate applications efficiently. Key Requirements: Proficiency in Java is required, with additional experience in Python as a plus. Experience with the JVM ecosystem, especially Spring Boot. Familiarity with frontend technologies, particularly Angular. Solid understanding of containerization technologies, including Docker and Kubernetes. Hands-on experience with AWS cloud services like Lambda, EC2, ECS, and EKS. Basic Terraform knowledge is essential. Minimum of 1-2 years working with AWS or equivalent experience with other cloud platforms. Knowledge of business process modeling or workflow orchestration tools such as Camunda or AWS Step Functions. Nice to Have: Experience with CI/CD pipelines. Familiarity with microservices architecture. Understanding of Agile methodologies. German languages Other Details: This position may offer remote work flexibility. The role is for a long-term assignment focusing on cloud-based technologies in a dynamic environment.