Karat role - Senior Software Engineer

🏢 Summary: Hybrid Senior Performance Test Engineer role focused on building automated performance testing frameworks and strategies for scalable, resilient digital products. The position uses JavaScript and k6 to test APIs, web applications, and distributed systems, embed testing in CI/CD, and drive performance improvements across engineering teams. 🗂️ Requirements: JavaScript (ES6+) proficiency, Automated test framework development experience, k6 performance testing experience, Load, stress, scalability testing and performance tuning knowledge, REST API and GraphQL API testing experience, CI/CD test integration experience, Git collaborative workflow experience, Docker and Kubernetes experience, Experience with AWS, Azure, or GCP, Observability and monitoring tool experience 📃 Skills: JavaScript, k6, REST, GraphQL, GitHubActions, GitLabCI, AzureDevOps, Jenkins, Git, Docker, Kubernetes, AWS, Azure, GCP, Grafana, Prometheus, ApplicationInsights 🏢 Description: Location: Warsaw, Poland (Hybrid – 2–3 days per week from office) About the Role We are looking for a Senior Performance Test Engineer to join our engineering team and help us build highly scalable, reliable, and resilient digital solutions. In this role, you will design and implement advanced performance testing strategies, develop automation frameworks, and work closely with engineering teams to identify bottlenecks and improve system performance. You will play a key role in embedding performance engineering practices into the software development lifecycle, enabling teams to deliver high-quality products that perform reliably at scale. This is an excellent opportunity for an experienced engineer who enjoys solving complex technical challenges, working with modern cloud technologies, and influencing engineering practices across distributed teams. Key Responsibilities Design, develop, and maintain performance testing frameworks and automation solutions using JavaScript (ES6+) . Create and execute performance, load, stress, and scalability testing strategies for modern applications. Develop and maintain performance test scenarios using k6 . Test and analyze the performance of: REST APIs GraphQL APIs Web applications and distributed systems Identify performance bottlenecks and provide actionable recommendations for optimization. Collaborate with developers, architects, DevOps, and product teams to improve system scalability and reliability. Integrate performance testing into CI/CD pipelines and engineering workflows. Support performance monitoring and analysis using observability platforms. Contribute to performance engineering standards, best practices, and continuous improvement initiatives. Work effectively with global, distributed engineering teams and communicate technical findings to both technical and non-technical stakeholders. Required Skills & Experience Strong proficiency in JavaScript (ES6+) . Proven experience building automated test frameworks and reusable testing solutions. Hands-on experience with k6 performance testing . Strong understanding of performance engineering methodologies, including: Load testing Stress testing Scalability testing Performance analysis and tuning Experience testing modern web applications and APIs, including: REST APIs GraphQL APIs Experience integrating automated tests into CI/CD pipelines , using tools such as: GitHub Actions GitLab CI Azure DevOps Jenkins Strong experience with Git and collaborative software development workflows. Solid understanding of software engineering principles and modern development practices. Excellent analytical and problem-solving skills. Cloud & Infrastructure Experience Experience working with modern cloud and infrastructure technologies: Docker and containerized environments. Kubernetes and cloud-native architectures. At least one major cloud platform: AWS Microsoft Azure Google Cloud Platform (GCP) Experience with observability and monitoring tools, such as: Grafana Prometheus Application Insights Similar monitoring and analytics platforms Soft Skills & Mindset Strong communication and stakeholder management skills. Ability to influence technical decisions and drive improvements without direct authority. Passion for quality engineering, automation, and developer enablement. Continuous learning mindset and curiosity about emerging technologies. Ability to collaborate effectively across international and distributed teams. Comfortable working independently while contributing to a highly collaborative engineering culture.

🏢 Summary: Senior Big Data Engineer role supporting a structured-finance data platform in a hybrid Warsaw setup, with up to two remote days per week. The position focuses on building scalable Spark/Scala data-processing solutions, production support, and collaboration in Agile delivery teams. 🗂️ Requirements: 3–5 years of Big Data engineering experience, Strong Spark expertise, Strong Java or Scala expertise, Knowledge of Python, Knowledge of DevOps practices, Knowledge of CI/CD tools, Knowledge of microservices, Fluent English, Existing legal right to work in the European Union 📃 Skills: Spark, Scala, Java, Python, DevOps, CI/CD, Microservices 🏢 Description: Hook – Ignite data-driven innovation in finance with cutting-edge Big Data solutions! Location & Work Model: Warsaw-based opportunity with hybrid work model, allowing up to 2 remote days per week. As a Senior Big Data Engineer (Spark/Scala) , you will be working for our client, a leader in structured finance within the global banking industry. You will contribute to building and optimizing a state-of-the-art data platform that supports complex business processes and fosters collaboration across multiple stakeholders in the financial sector. Join us to drive impactful data solutions that fuel digital transformation and open new avenues for growth. Your main responsibilities: Design and develop solutions for collecting, transforming, and processing large datasets efficiently. Analyze data from multiple sources and translate insights into technical specifications. Implement and industrialize reliable, scalable, and resilient data processing jobs using Spark and Scala. Conduct code reviews and collaborate with team members to ensure continuous improvement. Contribute to agile teams delivering value through Scrum cycles, supporting innovative project delivery. Stay up-to-date with evolving big data technologies and implement best practices. Support applications, troubleshoot production issues, and ensure high-quality standards. Produce comprehensive technical documentation, test plans, and project artifacts. You're ideal for this role if you have: 3-5 years of professional experience in big data engineering, preferably within banking or finance. Strong expertise in Spark and Java or Scala, with additional knowledge of Python, DevOps, CI/CD tools, and microservices. Fluent in English (additional Polish or French skills are a plus). An analytical mindset with excellent problem-solving skills. A proactive attitude and strong teamwork skills across global teams. Effective communication skills and ability to work across different time zones. It is a strong plus if you have: Knowledge of Airflow, GIT, and modern data architecture strategies. Experience with Agile methodologies and delivering solutions in fast-paced environments. Language Required for the role: Fluent English (required) Eligibility for the 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.

🏢 Summary: Senior Software Engineer role focused on designing, building, and scaling secure enterprise web applications and high-performance SaaS platforms. The position covers backend APIs, microservices, testing, technical leadership, and Azure-based CI/CD delivery within Agile teams. 🗂️ Requirements: 6+ years of full-lifecycle software development experience, Experience developing and maintaining large-scale web applications and SaaS solutions, Strong proficiency in C#, .NET Core, and .NET Framework, Hands-on experience with Azure Cloud services, RESTful architectures, and CI/CD pipelines, Experience with NUnit, Moq, Jest, and Git, Strong problem-solving and technical communication skills 📃 Skills: C#, .NET, Azure, REST, Microservices, NUnit, Moq, Jest, Git, CI/CD, SaaS 🏢 Description: We are looking for a skilled and passionate Senior Software Engineer to join our core engineering team. In this role, you will play a key part in designing, building, and scaling enterprise-grade web applications and high-performance SaaS solutions. If you have a strong foundation in Microsoft technologies, cloud architecture, and modern engineering practices—and love solving complex technical challenges—we would love to hear from you! Key Responsibilities Architecture & Development: Design, build, and maintain scalable, secure, and resilient web applications and SaaS platforms. API & Backend Systems: Implement and optimize RESTful APIs, microservices, and Web API integrations. Quality & Testing: Drive software quality by writing comprehensive unit tests (NUnit, Moq, Jest) and advocating for test-driven practices. Technical Leadership: Participate in code reviews, architectural discussions, and technical planning to ensure clean, maintainable code. Agile Collaboration: Work closely with cross-functional teams using Agile methodologies to deliver features iteratively and efficiently. DevOps & Version Control: Utilize Git and Azure DevOps for continuous integration, project tracking, and modern deployment pipelines. Key Requirements Experience: 6+ years of hands-on experience in full-lifecycle software development. SaaS & Web Architecture: Proven track record of developing and maintaining large-scale web applications and SaaS solutions. Core Tech Stack: Strong proficiency in C# , .NET Core , and .NET Framework . Cloud & DevOps: Hands-on experience with Azure Cloud services, RESTful architectures, and CI/CD pipeline concepts. Testing & Tools: Solid experience with unit testing frameworks ( NUnit, Moq, Jest ) and version control ( Git ). Communication: Excellent problem-solving skills and the ability to articulate technical concepts clearly to team members. Nice to Have Agile Frameworks: Experience working within a SAFe (Scaled Agile Framework) environment. Mentorship: Passion for coaching junior developers and fostering team growth.

🏢 Summary: Senior Software Engineer role on a global product team building enterprise platforms for research, clinical development, and scientific decision-making. The position focuses on scalable backend services, modern web applications, cloud-native architecture, CI/CD, testing, reliability, and collaboration in an agile environment. 🗂️ Requirements: 5+ years of software development experience, ASP.NET Core and Vue 3 with TypeScript, Python or .NET backend experience, REST API development, Azure or AWS cloud experience, GitHub Actions CI/CD experience, Automated testing and DevOps practices, English fluency 📃 Skills: ASP.NET, Core, .NET, Vue, TypeScript, Python, REST, Azure, AWS, GitHub, Actions, Vitest, Allure, MSAL 🏢 Description: About the role Are you an experienced Software Developer looking to build digital products that deliver real business value? Join a global product team developing enterprise-grade platforms that support research, clinical development, and scientific decision-making. You will work closely with Product Owners, architects, business stakeholders, and fellow engineers to design, build, and evolve modern software solutions used by thousands of users worldwide. What you will be doing • Design and implement scalable solutions with backend services and APIs • Develop modern web applications and user-facing functionality • Contribute to system architecture and technical decision-making • Participate in cloud-native solution design and implementation • Build and improve CI/CD pipelines and automated deployment processes • Ensure high quality through automated testing and code reviews • Collaborate with cross-functional teams in an agile setup • Support platform reliability, observability, and operational excellence What we are looking for • 5+ years of software development experience • Frameworks: ASP.NET Core (.NET 10), Vue 3 (Composition API) + TypeScript • UI library: internal design system • Auth: Azure MSAL Browser (Microsoft identity) • Testing: Vitest + Vue Test Utils, Allure reporting • Hands-on experience with at least one backend technology stack such as: Python, .NET • Experience developing REST APIs • Experience with cloud platforms such as Azure or AWS • Experience with CI/CD (GitHub Actions), automated testing, and DevOps practices • Strong communication and stakeholder management skills • Experience from regulated environments is considered an advantage • Fluency in English, both written and spoken, is expected.

🏢 Summary: Hybrid Senior Big Data Engineer offer focused on building and optimizing a financial data platform for structured-finance workflows. The role involves designing scalable Spark and Java data-processing solutions, supporting production systems, and collaborating in Agile global teams. 🗂️ Requirements: 3–5 years of big data engineering experience, Strong Spark expertise, Strong Java expertise, DevOps knowledge, CI/CD knowledge, Microservices knowledge, Fluent English, Legal right to work in the European Union 📃 Skills: Java, Spark, Python, DevOps, CICD, Microservices, Airflow, Git, Scrum 🏢 Description: Unleash the power of big data to revolutionize financial technology — drive innovation at the forefront of banking transformation! Warsaw-based opportunity with hybrid work model (up to 2 days remote per week). As a Senior Big Data Engineer – Java and Spark , you will be working for our client, a leader in structured finance within the global banking industry. You will contribute to building and optimizing a state-of-the-art data platform that supports complex financial workflows and fosters collaboration across multiple stakeholders. Join us to shape impactful data solutions that fuel digital transformation and unlock new growth avenues—your expertise will propel innovation in the financial sector. Your main responsibilities: Design and develop solutions for collecting, transforming, and processing large datasets efficiently. Analyze data from multiple sources and translate insights into detailed technical specifications. Implement and industrialize reliable, scalable, and resilient data processing jobs using Spark and Java. Conduct code reviews and collaborate with team members to ensure continuous improvement. Contribute to Agile teams delivering value through Scrum cycles and support innovative project delivery. Keep up-to-date with evolving big data technologies and apply best practices. Support applications, troubleshoot production issues, and ensure high-quality standards. Produce comprehensive technical documentation, test plans, and project artifacts. You’re ideal for this role if you have: 3-5 years of professional experience in big data engineering, ideally within banking or finance sectors. Strong expertise in Spark and Java, with additional knowledge of Python (nice to have), DevOps, CI/CD tools, and microservices. Fluent in English (spoken and written). Analytical mindset with excellent problem-solving skills. Proactive attitude with strong teamwork capabilities across global teams. Effective communication skills and ability to operate across different time zones. It is a strong plus if you have: Knowledge of Airflow, GIT, and modern data architecture strategies. Experience with Agile methodologies and delivering solutions in fast-paced environments. Language Required for the role: Fluent English. Eligibility for the role: Only candidates with an existing legal right to work in the European Union will be considered. #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.

🏢 Summary: Senior Big Data Engineer role building and optimizing a financial data platform for structured-finance workflows. The position focuses on scalable Spark and Java data-processing solutions, production support, and Agile collaboration in a hybrid Warsaw-based model. 🗂️ Requirements: 3–5 years of big data engineering experience, Strong Spark expertise, Strong Java expertise, Knowledge of DevOps, CI/CD, and microservices, Fluent English, Legal right to work in the European Union 📃 Skills: Spark, Java, DevOps, CI/CD, Microservices, Python, Airflow, Git, Scrum 🏢 Description: Location & Work Model Warsaw-based opportunity with a hybrid work model, with up to 2 remote days per week. Description As a Senior Big Data Engineer – Java and Spark, you will work on building and optimizing a state-of-the-art data platform supporting complex financial workflows and collaboration across multiple stakeholders. The role focuses on delivering impactful data solutions that support digital transformation in the financial sector. Responsibilities • Design and develop solutions to collect, transform, and process large datasets efficiently. • Analyze data from multiple sources and translate insights into detailed technical specifications. • Implement and industrialize reliable, scalable, and resilient data-processing jobs using Spark and Java. • Conduct code reviews and collaborate with team members to drive continuous improvement. • Contribute to Agile teams delivering value through Scrum cycles and support innovative project delivery. • Keep current with evolving big-data technologies and apply best practices. • Support applications, troubleshoot production issues, and maintain high-quality standards. • Produce comprehensive technical documentation, test plans, and project artifacts. Requirements • 3–5 years of professional experience in big data engineering, ideally in banking or finance. • Strong expertise in Spark and Java. • Knowledge of DevOps, CI/CD tools, and microservices. • Fluent written and spoken English. • Analytical mindset and excellent problem-solving skills. • Proactive approach and strong teamwork skills in global teams. • Effective communication skills and ability to work across time zones. • Existing legal right to work in the European Union. Preferred Qualifications • Knowledge of Python. • Knowledge of Airflow, Git, and modern data-architecture strategies. • Experience with Agile methodologies and delivering solutions in fast-paced environments.