Kotlin Engineer – (Senior/Staff)

🏢 Summary: Join a developer tooling initiative supporting a large-scale migration to JFrog Artifactory. The role focuses on Python-based automation, CLI tools, REST APIs, microservices, CI/CD workflows, and dependency management for enterprise engineering teams. 🗂️ Requirements: Advanced Python proficiency, Experience with FastAPI or Flask, Relational and non-relational database knowledge, Docker and container registry experience, CI/CD pipeline design and optimization, Performance, stress, and latency testing experience, Git and Git-based workflow proficiency, English B2/C1, Polish B2/C1 📃 Skills: Python, FastAPI, Flask, Docker, SQL, NoSQL, Jenkins, GitLab, GitHub, Git, GitOps, Artifactory, JFrog, CI/CD, REST, Microservices 🏢 Description: VirtusLab is a leading European software consulting and engineering company. Our mission is to craft clean code and practical solutions with precision and purpose. We foster a dynamic culture rooted in strong engineering, a sense of ownership, and transparency, empowering professionals to make a substantial impact in the software industry. About The engagement involves collaborating with a specialized Dev-Tooling / Software Engineering stream focused on supporting a large-scale migration from a legacy in-house artifact storage solution to JFrog Artifactory. Python & API development: Advanced Python Web Frameworks (preferably FastAPI): Advanced Docker : Regular Relational & Non-relational databases (SQL, NoSQL) Regular CI/CD: Regular Jenkins: Regular Artifactory: Nice to have English: Advanced Polish: Advanced Project: Smart Artifacts Engine Project Scope Artifactory will serve as the central repository across the enterprise for high-volume binary assets, compiled packages, software libraries, and large data files. Given the massive scale of the artifact repository and the complexity of the migration, this initiative is driven by software engineering and automation rather than standard operational DevOps tasks. The primary focus centers on developing robust, reliable developer tools and services to streamline the onboarding experience and automate workflows for engineering teams across enterprise environments. Scope of services Developer Tooling Engineering: Designing, building, and maintaining automation scripts, CLI tools, and background services to facilitate seamless artifact migration and continuous integration. Onboarding & Workflow Automation: Delivering automated onboarding mechanisms for internal dev teams, simplifying dependency handling, package publishing, and access management. Dependency Management Optimization: Resolving complex dependency resolution challenges in Python and Docker environments during high-throughput repository transitions. Lightweight Backend Development: Creating internal REST APIs and microservices to support migration operations and integrating Artifactory into the existing tooling ecosystem. Project Enviroment The project team operates in a distributed setup between New York and London. With the primary Technical Lead based in New York, the engagement offers high flexibility, allowing seamless cooperation aligned with European business hours. What we expect in general Strong proficiency in Python with expertise in building clean, maintainable code, test automation frameworks, and backend services (e.g., FastAPI, Flask). Solid understanding of database systems, both relational (SQL) and non-relational (NoSQL), including schema design and query optimization. Hands-on experience with containerization (Docker) and container registry management, with a focus on optimizing image sizes and build times. Proven track record of designing, maintaining, and optimizing robust CI/CD pipelines (e.g., GitLab CI, GitHub Actions, Jenkins) supporting automated testing and artifact deployment. Experience in designing and executing performance, stress, and latency testing solutions, with a strong focus on tracking capacity and system metrics. Strong proficiency with Git (version control, branching strategies, conflict resolution) and Git-based workflows (e.g., GitOps, Pull/Merge Requests). Good command of English (B2/C1). Good command of Polish (B2/C1) A few perks of being with us Building tech community Flexible hybrid work model Home office reimbursement Language lessons MyBenefit points Private healthcare Training Package Virtusity / in-house training Access to the above perks is optional and completely voluntary for B2B contractors

🏢 Summary: Infrastructure engineering engagement supporting a large-scale developer ecosystem through Linux/Unix operations, Python automation, graph database security, and data-platform modernization. The role owns infrastructure delivery, dependency mapping, monitoring, and integration of Python- and Java-based data pipelines, with a focus on reliability and security. 🗂️ Requirements: 5+ years of commercial system administration or infrastructure engineering experience, Linux/Unix administration, Networking concepts, Python infrastructure automation and scripting, Complex system performance troubleshooting, English proficiency at B2/C1 level or higher 📃 Skills: Linux, Unix, Python, Networking, Kafka, Java, GraphDB, Neo4j, GraphQL, Kubernetes, Snowflake 🏢 Description: VirtusLab is a leading European software consulting and engineering company. Our mission is to craft clean code and practical solutions with precision and purpose. We foster a dynamic culture rooted in strong engineering, a sense of ownership, and transparency, empowering professionals to make a substantial impact in the software industry. Project Overview & Engagement Profile This engagement involves key infrastructure delivery built around graph databases (GraphDB / Neo4j). The focus combines high-level systems engineering and infrastructure automation with proactive security standards and system architecture optimization. Key Areas of Delivery: Infrastructure Operations & Automation: Administering Linux/Unix environments and engineering infrastructure automation utilizing Python. Database Hardening & Security: Hardening graph database environments, implementing top-tier security standards, and designing monitoring and alerting mechanisms. Dependency Mapping: Analyzing and mapping technical dependencies between databases, data pipelines, and enterprise-wide systems. Data Infrastructure: Engineering and optimizing data processing pipelines integrating Python- and Java-based components. Technical Driving & Autonomy: Collaborating independently with technical stakeholders, driving solutions, and owning delivery outcomes. Linux/Unix Administration Advanced Python Advanced Kafka/Streaming Data Regular Kubernetes Regular Java (Data pipelines / APIs) Nice to have GraphDB (Neo4j)/GraphQL Nice to have English Advanced View available projects Project: ESM Project Scope Supporting a large-scale enterprise ecosystem powering thousands of software developers by maintaining and modernizing core infrastructure and data platforms. The project focuses on end-to-end infrastructure operations, automation, and data pipeline integrations. Key architectural priorities include mapping, tracing, and securing graph data connections (GraphDB) across the ecosystem, while maintaining rigorous security hardening, robust monitoring, and proactive alerting. Tech stack Linux / Unix Automation & Scripting: Python Data Pipelines & Integration: Java, Apache Kafka (Streaming Data) Databases & Graph Technologies: GraphDB, Neo4j, GraphQL Containerization & Orchestration: Kubernetes Key Challenges Database Security & Observability: Hardening GraphDB instances to meet strict enterprise security standards while establishing reliable tracing, monitoring, and alerting across boundaries. Architecture Mapping: Tracing and mapping graph database interconnections across enterprise systems. Cross-Language Pipeline Integration: Automating and optimizing data processing pipelines across Python and Java stacks. Scale & Reliability: Supporting a high-scale developer ecosystem with maximum availability and seamless delivery. Project Delivery Model Services are provided within a modern Data Platform Engineering domain. Consultants deliver specialized expertise through structured alignment with key project areas, maintaining high technical synchronization while fostering a strong platform knowledge-sharing environment. Expected Capabilities & Expertise: Solid background in Linux administration and deep understanding of networking concepts Proven expertise in using Python for infrastructure automation, scripting, and system tool development Advanced analytical capabilities for diagnosing, troubleshooting, and resolving complex system performance issues at scale 5+ years of commercial experience in system administration or infrastructure engineering English proficiency at B2/C1 level or higher, enabling seamless technical communication Nice to Have: Practical experience with Kafka Working knowledge of Java Hands-on experience with Graph Databases (e.g., Neo4j) or query-layer technologies (GraphQL APIs, Semantic Views) Experience in building or maintaining data ingestion pipelines Hands-on knowledge of Kubernetes Familiarity with the Snowflake data platform Solid understanding of networking topologies and firewall technologies A few perks of being with us Building tech community Flexible hybrid work model Home office reimbursement Language lessons MyBenefit points Private healthcare Training Package Virtusity / in-house training Access to the above perks is optional and completely voluntary for B2B contractors

🏢 Summary: Join a strategic engineering initiative to standardize behavioural-event tracking and data quality across a large product ecosystem. The role involves investigating event sources, implementing Java/Kotlin backend and API changes, integrating Segment, and making occasional React frontend updates through the end of the year. 🗂️ Requirements: 5+ years of commercial Java and Kotlin experience, Experience maintaining existing systems across multiple repositories or codebases, Ability to investigate issue origins, system ownership and dependencies, Strong cross-team communication with engineers and stakeholders, Pragmatic approach to legacy systems and organisational complexity, Basic React knowledge for web frontend adaptations, Practical use of AI tools for engineering discovery, implementation or validation 📃 Skills: Java, Kotlin, React, APIs, AI 🏢 Description: Join a new engineering team and help standardize how one of Austria’s largest digital platforms captures and activates user-behaviour data. You’ll support a strategic data-driven initiative focused on standardizing tracking events, improving data quality and enabling marketing and other business teams to make better use of behavioural data. This is not about delivering tickets within a single backend service. You’ll navigate an extensive product ecosystem, identify where events originate, collaborate with system owners and implement changes across backend, web and data-platform integrations. Tech stack: Java, Kotlin, React, APIs, Segment, event tracking and customer data platforms. The assignment is planned to run until the end of this year. Your everyday playground: Improve and standardize tracking events across product ecosystem. Investigate where particular events are generated and identify the relevant projects, repositories and system owners. Design and implement backend and API changes using Java and Kotlin. Integrate behavioural data with Segment and the wider data ecosystem. Make necessary adjustments in the React-based web application when required. Raise technical risks, clarify dependencies and involve other developers when a change requires broader coordination. Move between different repositories and systems while taking ownership of each topic from discovery to delivery. What are we looking for? 🕵️‍♀️ Strong commercial experience with Java and Kotlin (min. 5 years of experience) Experience working with existing systems and navigating multiple repositories or codebases. A proactive discovery mindset: you know how to identify where a problem originates, who owns the relevant system and what context is needed before making a change. Strong communication skills and confidence in approaching engineers and stakeholders from other teams. A pragmatic approach to legacy systems and organisational complexity. Basic React knowledge that allows you to make necessary adaptations in a web frontend application. Practical use of AI tools to accelerate engineering discovery, implementation or validation. Bonus points: Experience with Segment or a comparable Customer Data Platform. Experience with event tracking, product analytics or marketing analytics. Knowledge of event-taxonomy or event-schema design. Experience integrating backend, web and mobile applications with data or analytics platforms. Understanding of data quality, tracking consistency and behavioural-data flows. Experience supporting initiatives that span several engineering teams or product areas. Why join us? 🌟 A meaningful initiative: you’ll contribute to a strategic programme that supports data-driven marketing and future business use cases. Real engineering ownership: the desired outcome is defined, but you’ll have autonomy in deciding how to implement it safely and effectively. Work beyond a single repository: you’ll investigate systems, map dependencies and collaborate with the people who understand each product area best. Sounds like a fit? Let’s talk! 🚀

🏢 Summary: Senior Deployment and Integration Engineer role delivering AI-platform deployments and reusable client integrations from MVP and pilot through production and BAU. The fully remote B2B contract uses Kotlin and Java on GCP, with responsibilities spanning real-time voice integrations, cloud infrastructure, testing, production support and mentoring. 🗂️ Requirements: Commercial Kotlin experience, Commercial Java experience, Hands-on GCP experience, Terraform and cloud provisioning experience, CI/CD and containerised deployment experience, REST API, microservices, third-party API, webhook and SDK integration experience, PostgreSQL, Redis and Firestore experience, Authentication and API security knowledge, Unit, integration and API testing experience, UAT and production deployment support experience, Logging, monitoring and production troubleshooting experience, Reusable integration delivery experience, Real-time or agentic integration experience, Client technical-requirements translation experience, Full delivery lifecycle experience: MVP, pilot, UAT, production and BAU, English proficiency 📃 Skills: Kotlin, Java, GCP, Terraform, CI/CD, Containers, REST, Microservices, Webhooks, SDKs, PostgreSQL, Redis, Firestore, SIP, WebRTC, APIs, UAT, MVP, BAU 🏢 Description: We are looking for a Senior Deployment and Integration Engineer to join a client-facing engineering team working on an AI-powered platform and its integrations. In this role, you will take ownership of client deployments and integrations end to end — from MVPs and pilots through integration, testing and UAT to production deployment, maintenance and BAU support. You will work closely with an international engineering team, including senior engineers based in Canada, to deliver new and more complex integrations. A key part of the role is turning integrations into reusable capabilities . Rather than building bespoke solutions for every customer, you will generalise new integrations so they can be efficiently deployed for future clients using the same providers and platforms. You will also help onboard and mentor additional deployment and configuration engineers as the team grows. The project is fully remote and delivered within the client's controlled virtual desktop environment, where all code and data remain. The core technology stack is Kotlin and Java on GCP . In Short 🌎 100% REMOTELY or from one of our 2 offices 💰 150 - 180 PLN/h + VAT ☑️ B2B contract Your Daily Missions Owning standard client deployments and integrations from MVP / pilot through production and BAU. Working with senior engineers on new and complex third-party integrations. Building and maintaining integrations with contact-centre, telephony and other external platforms. Working with real-time voice technologies, including SIP, WebRTC, voice streaming, speech-to-text and text-to-speech . Developing and integrating REST APIs, microservices, webhooks and SDKs. Turning newly delivered integrations into generalised, reusable solutions for future clients. Working with Kotlin and Java services running on GCP. Provisioning cloud infrastructure and supporting automated deployments using Terraform, CI/CD and containers. Working with PostgreSQL, Redis and Firestore. Writing and maintaining unit, integration and API tests. Supporting UAT, production deployments, monitoring, logging and troubleshooting. Working directly with customer technical teams to translate requirements into effective technical solutions. Using AI coding tools to quickly understand and contribute to an established codebase while carefully verifying generated output. Supporting and mentoring engineers joining the deployment and configuration team. The Essentials We’re Seeking Strong commercial experience with Kotlin and Java . Strong hands-on experience with Google Cloud Platform (GCP) . Experience with Terraform, CI/CD, containerised deployments and cloud infrastructure provisioning . Strong experience building and integrating REST APIs, microservices, third-party APIs, webhooks and SDKs . Experience with PostgreSQL, Redis and Firestore . Solid understanding of authentication and API security principles. Experience with unit, integration and API testing as well as supporting UAT. Hands-on experience with production deployments, logging, monitoring and troubleshooting. A proven track record of building integrations for reuse — creating a solution once and generalising it for subsequent clients rather than repeatedly delivering bespoke implementations. Experience with real-time or agentic integrations , ideally involving contact-centre or telephony platforms, SIP, WebRTC, real-time voice streaming, speech-to-text or text-to-speech. Ability to ramp up quickly in a mature codebase you did not build, including effective use of AI coding tools combined with strong engineering judgement and verification. Strong client-delivery mindset and the ability to translate customer requirements into technical implementation. Confidence working across the complete delivery lifecycle: MVP, pilot, UAT, production and BAU. Strong troubleshooting and problem-solving skills in production environments. Ability to work effectively with customer technical teams and mentor other engineers. Strong written and spoken English , used daily in an international environment. Nice-to-haves Experience with Pub/Sub, queues and event-driven processing . Experience with Vertex AI or OpenAI APIs . Experience integrating LLMs, AI agents or conversational AI solutions . Experience designing or operating high-availability and high-performance systems . Experience in collections, contact-centre or financial-services environments . Reasons Why You Would Enjoy Working With Us We work in the latest technologies and with international clients, and our projects are polished from < to /> - learn about some of the projects we have completed. We organize TechTalks, meet-ups and create guilds where we exchange knowledge - you can learn a lot from your teammates. We have a close-knit team and we make sure to have regular integrations - we often go out to celebrate together. You can work remotely or choose to work from our offices in Wroclaw or Bielsko-Biala. However, we count on your openness to occasionally visit the office for team meetings or client visits, or possible occasional trips to the client's headquarters. You can adjust your working hours to suit your needs, starting your day between 7:00 and 10:00 am. You can work with great specialists in their fields who also have a sense of humor and other after-hours hobbies. It is the people who create the unique atmosphere and relaxed atmosphere at CSHARK. We have a flat structure - we are not a corporation and don't want to be one 🙃. We offer bonuses for employee referrals (from 3000 PLN to 7000 PLN). We organize remote English classes and provide access to the company library. You can also become an author/author of articles published on our technical blog - https://cshark.com/blog/ .

🏢 Summary: Senior Full-Stack Kotlin Engineer contract role focused on building station-management products that improve passenger experiences and support internal teams. The consultant will drive roadmap epics, align technical solutions with stakeholders, and deliver cloud-deployed software in an agile, CI/CD-driven environment. 🗂️ Requirements: 5+ years of software engineering experience, Primarily backend development experience with a JVM language, Commercial Kotlin experience, Solid modern front-end development skills, Hands-on cloud application automation and deployment experience, CI/CD pipeline and DevOps best-practice experience, System design and architecture proficiency, Solid written and spoken English 📃 Skills: Kotlin, JVM, Frontend, AWS, Azure, CI/CD, DevOps, Cloud, Automation, Testing, Architecture 🏢 Description: We are looking for a skilled Senior (Full-Stack) Kotlin Engineer as service agreement collaborator. Flix customers worldwide expect a comfortable and seamless experience at our stations as part of their travel experience. Our self-organized, cross-functional and distributed team builds products to enable Flix station managers to scale management of the station inventory, which a wide range of internal tech teams across Flix depend on, and overall serves to improve the experience at our stations for millions of passengers. Scope of services Independent management of roadmap epics as topic driver, aligning technical requirements and solutions across the Flix teams together with the product owner Close interaction with business stakeholders on continuously developing and improving the product vision with business driven mindset Supporting the development process using an agile environment Pair and ensemble programming, code reviews, testing, and operations Delivery of new versions of the product, using continuous integration and delivery Relevant experience 5+ years of software engineering experience, primarily backend development with a JVM language, including some commercial experience with Kotlin Solid front-end skills with modern front-end stack Experience with event-driven architectures; exposure to event sourcing, CQRS, and domain-driven design (DDD) is a plus Hands-on experience with automation and deployment of applications into cloud infrastructure (e.g., AWS, Azure) using CI/CD pipelines and DevOps best practices Proficiency in system design and architecture Solid written and spoken English communication skills