Senior Backend Engineer [.Net] (work until 9 p.m. CET)

🏢 Summary: Development role focused on building and modernizing a large-scale, microservice-based ticket sales platform running on AWS. The position involves backend development in .NET 7/8, creating new features and refactoring existing components within an Agile environment. It offers strong engineering practices, continuous integration, and collaboration within multiple backend squads. 🗂️ Requirements: 3–5 years of backend development experience, 3–5 years of commercial development on .NET platform, Strong knowledge of C#, Practical experience with AWS, Understanding of Clean Code and OOP, Knowledge of SOLID principles, Experience with WebAPI, Understanding of microservices architecture, Experience with unit testing (e.g., nUnit), Experience with mocking frameworks (e.g., Moq), Experience with dependency injection (e.g., Autofac), Knowledge of Entity Framework or NHibernate, Experience with DBMS systems, Understanding of Agile methodology, Good spoken English 📃 Skills: .NET, C#, AWS, REST, WebAPI, Microservices, nUnit, Moq, Autofac, EntityFramework, NHibernate, Postgres, DynamoDB, MSSQL, RDS, CI 🏢 Description: Client Our client is one of the regional leaders in the industry and is currently launching a new product—an international platform for ticket sales. The company’s annual revenue exceeds €100 million. Join a great company, not merely an individual project Project overview The client uses various tools to reach their customers, such as a mobile app, a responsive web application, or communicating with them directly through the call center. The system is big and modular (microservice-based), complying with a number of regulations. We provide APIs for different clients including the biggest Global Distribution Systems (GDSes). We also provide solutions that are labeled by more than half of Train Operating Companies (TOCs) in the UK. Our client is committed to ensuring that the system will be as modern as possible. It is based on a microservice architecture with the use of continuous integration, where a few hundred components operate independently of each other and can be used as they become available. This increases the modularity of the system and optimizes the use of the services. All components run on AWS. The backend also includes .NET 7/8, and REST API is actively modernized to Cloud Native solutions (RDS like Postgres, DynamoDB) from MSSQL. The client has a policy to work with the latest technology, and they move to newer versions when they are available. Team Several independent teams are working on the project. The goals of each team are limited to the part of the system they're working on. DataArt's specialists are working on the backend in several teams. The project has a team of 30+ .NET developers who work on the backend, divided into smaller squads. Position overview DataArt is currently helping develop new features and modernize the IT system of an independent online railroad ticket retailer. The project is a great place to work and grow for Middle engineers due to strong engineering practices (microservices, clean code, extensive unit testing, CI, dozens of production deployments weekly, the Scout Rule, code reviews, and an Agile approach), continuous technical refactoring, and a senior team that is willing to learn and share experience. Responsibilities Development of new features, expanding the ticket-selling system + refactoring 80-90% backend development 20-10% team meetings Requirements From 3 to 5 years of backend development experience From 3 to 5 years of experience in commercial software development on the .NET platform Understanding of and experience working with C# Good understanding of Cloud - AWS practical experience mandatory Strong skills in Clean Code and OOP Understanding of SOLID principles Knowledge of WebAPI Understanding of microservices architecture Experience with unit testing (like nUnit) and mocking frameworks (preferred Moq) Experience with dependency injection (preferred Autofac) Knowledge of Entity Framework or NHibernate Experience working with any DBMS system Understanding of Agile development methodology Good spoken English 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.)

🏢 Summary: Senior .NET Developer role focused on designing and maintaining a long-term Portfolio Management System combining backend services, desktop applications, and system integrations. The position involves building data-intensive solutions, RESTful services, messaging components, and WCF integrations within a CI/CD-driven environment. You will work across backend and desktop layers to deliver reliable, scalable software. 🗂️ Requirements: Commercial experience with C# and .NET, Hands-on experience with VSTO, Experience developing backend applications, Experience implementing RESTful APIs, Hands-on experience with WCF services, Strong experience with Entity Framework, Strong experience with ADO.NET, Practical knowledge of MS SQL Server, Experience with relational database design, Experience with WPF, Familiarity with RabbitMQ or message queues, Understanding of CI/CD pipelines 📃 Skills: C#, .NET, VSTO, WCF, WPF, REST, EntityFramework, ADO.NET, MSSQL, RabbitMQ, CI/CD, ASP.NET, Azure, TeamCity, WinServices 🏢 Description: Project overview The project focuses on building and evolving a Portfolio Management System that includes backend services, messaging, and desktop-based user interfaces. The solution integrates multiple systems, processes large volumes of data, and supports continuous delivery through automated pipelines. Team You will work in a cross-functional team consisting of backend developers, desktop developers, QA engineers, and DevOps specialists. The team collaborates closely through code reviews, shared technical discussions, and iterative delivery. Position overview We are looking for a Senior .NET Developer to work on a long-term Portfolio Management System that combines backend services, desktop applications, and system integrations. You will be involved in designing, developing, and maintaining reliable software solutions that support complex business processes and data-intensive workflows. Technology stack C#, .NET, Entity Framework, ADO.NET , MS SQL Server, RESTful APIs, RabbitMQ, CI/CD pipelines, VSTO, WPF, WCF, Win Services, ASP.NET , MS Azure, and TeamCity Responsibilities Design and develop backend services using C# and .NET Develop, support, and enhance WCF services to enable reliable internal and external system integrations Implement and maintain RESTful APIs for internal and external integrations Work with MS SQL Server using Entity Framework and ADO.NET Develop and support desktop applications using WPF and VSTO Integrate asynchronous messaging solutions using RabbitMQ Collaborate with the team on architecture decisions and technical improvements Participate in code reviews, contribute to code quality, and maintainability Support CI/CD processes and ensure smooth delivery of new features Requirements Commercial experience with C# and the .NET platform Hands-on experience developing VSTO-based solutions Experience developing backend applications and RESTful APIs Hands-on experience developing and maintaining WCF services Strong practical experience with Entity Framework and ADO.NET Practical knowledge of MS SQL Server and relational database design Experience with WPF for desktop application development Familiarity with message queues, preferably RabbitMQ Understanding of CI/CD principles and automated delivery pipelines Ability to work collaboratively in a team-oriented environment Nice to have Exposure to large-scale or enterprise-level systems Experience in maintaining legacy applications alongside new development Basic knowledge of application performance optimization and troubleshooting 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.)

🏢 Summary: Senior .NET Backend Developer role focused on modernizing and expanding a complex international ticket sales platform built on microservices architecture and hosted on AWS. The position involves developing and maintaining scalable backend services, refactoring existing systems, and collaborating with cross-functional teams. The project uses the latest .NET technologies and supports integration with multiple external systems including GDS APIs. 🗂️ Requirements: 7+ years of backend development experience, 7+ years of commercial development experience on .NET platform, Strong proficiency in C# and .NET, Experience with RESTful WebAPI, Experience working with microservices architecture, Experience with unit testing frameworks (e.g., nUnit), Experience with mocking frameworks (e.g., Moq), Experience with dependency injection (e.g., Autofac), Experience with Entity Framework or NHibernate, Experience with DBMS systems, Understanding of Clean Code and OOP principles, Understanding of SOLID principles, Understanding of Agile methodology, Good spoken English 📃 Skills: .NET, C#, REST, WebAPI, Microservices, MSSQL, PostgreSQL, DynamoDB, AWS, nUnit, Moq, Autofac, EntityFramework, NHibernate, OOP, SOLID, Agile, JWT, OAuth2, OpenID 🏢 Description: Client The company is one of the regional leaders in the industry and is currently launching their new product, an international platform for ticket sales. The company's annual income exceeds 100 million euros. Join a great company, not merely an individual project Project overview The client uses various tools to reach their customers, such as a mobile app, a responsive web application, or communicating with them directly through the call center. The system is very complex, it must comply with a large number of regulations. We provide APIs for different clients including the biggest Global Distribution Systems (GDSes). Our client is committed to ensuring that the system will be as modern as possible. It is based on microservice architecture with the use of continuous integration, where a few hundred components operate independently of each other and can be used as they become available. This increases the modularity of the system and optimizes the use of the services. All components run on AWS. Team Several independent teams are working on the project. The goals of each team are limited to the part of the system they're working on. DataArt's specialists are working on the back-end in one of the teams. Position overview DataArt is currently helping to modernize and develop the IT system of an independent online retailer of railroad tickets. Technology stack .NET (always working with newest versions) microservices REST API MSSQL migrating to Postgres, DynamoDB Responsibilities Refactoring and expanding tickets selling system Develop, enhance, and maintain high-quality, scalable code Work collaboratively with cross-functional teams to support the implementation of new features and achieve their objectives Requirements 7+ years of backend development experience 7+ years of experience in commercial software development on the .NET platform Understanding of and experience working with C# Development experience with .NET Strong skills in Clean Code and OOP Knowledge of WebAPI Understanding of microservices architecture Experience with unit testing (like nUnit) and mocking frameworks (preferred Moq) Experience with dependency injection (preferred Autofac) Knowledge of Entity Framework or NHibernate Experience working with any DBMS system Understanding of SOLID principles Understanding of Agile development methodology Good spoken English Nice to have Knowledge of basic Authentication: types of Authentication, JWT, OAuth 2.0, OpenId Connect 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.)

🏢 Summary: Backend .NET Developer role focused on modernizing and expanding a large-scale international ticket sales platform built on microservices and deployed on AWS. The position involves developing and refactoring a complex, regulation-compliant system that integrates with external clients via REST APIs. You will work on scalable backend services within a distributed architecture supporting web and mobile applications. 🗂️ Requirements: 7+ years backend development experience, 7+ years commercial .NET development, Strong C# knowledge, Experience with .NET WebAPI, Experience with microservices architecture, Experience with unit testing frameworks, Experience with dependency injection, Experience with ORM frameworks, Experience with relational or NoSQL databases, Knowledge of Clean Code, OOP, SOLID, Experience in Agile environment 📃 Skills: .NET, C#, WebAPI, REST, Microservices, MSSQL, PostgreSQL, DynamoDB, AWS, nUnit, Moq, Autofac, EntityFramework, NHibernate, OOP, SOLID, JWT, OAuth2, OpenIdConnect, Agile 🏢 Description: Client The company is one of the regional leaders in the industry and is currently launching their new product, an international platform for ticket sales. The company's annual income exceeds 100 million euros. Project overview The client uses various tools to reach their customers, such as a mobile app, a responsive web application, or communicating with them directly through the call center. The system is very complex, it must comply with a large number of regulations. We provide APIs for different clients including the biggest Global Distribution Systems (GDSes). Our client is committed to ensuring that the system will be as modern as possible. It is based on microservice architecture with the use of continuous integration, where a few hundred components operate independently of each other and can be used as they become available. This increases the modularity of the system and optimizes the use of the services. All components run on AWS. Team Several independent teams are working on the project. The goals of each team are limited to the part of the system they're working on. DataArt's specialists are working on the back-end in one of the teams. Position overview DataArt is currently helping to modernize and develop the IT system of an independent online retailer of railroad tickets. Technology stack .NET (always working with newest versions) microservices REST API MSSQL migrating to Postgres, DynamoDB Responsibilities Refactoring and expanding tickets selling system Develop, enhance, and maintain high-quality, scalable code Work collaboratively with cross-functional teams to support the implementation of new features and achieve their objectives Requirements 7+ years of backend development experience 7+ years of experience in commercial software development on the .NET platform Understanding of and experience working with C# Development experience with .NET Strong skills in Clean Code and OOP Knowledge of WebAPI Understanding of microservices architecture Experience with unit testing (like nUnit) and mocking frameworks (preferred Moq) Experience with dependency injection (preferred Autofac) Knowledge of Entity Framework or NHibernate Experience working with any DBMS system Understanding of SOLID principles Understanding of Agile development methodology Good spoken English Nice to have Knowledge of basic Authentication: types of Authentication, JWT, OAuth 2.0, OpenId Connect 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.)

🏢 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.)

🏢 Summary: Senior .NET Developer / Architect role focused on building and optimizing a cloud-native travel booking platform in a microservices architecture. The position involves designing high-performance flight search and booking flows, integrating with GDS/NDC APIs, and ensuring scalability, reliability, and low-latency performance. The role combines deep technical expertise in distributed systems with strong domain knowledge in airline and travel technology. 🗂️ Requirements: 5+ years experience with C# and .NET, 5+ years experience in travel industry (flight shopping, booking engines, OTA, metasearch), Experience with GDS systems (Sabre, Amadeus, Travelport) and/or NDC APIs, Knowledge of airline concepts (PNR, e-ticketing, fare rules, availability, schedule changes), Experience with cloud-native and distributed architectures, Experience with high-throughput, low-latency systems, Experience with observability tools, Ability to design scalable APIs and asynchronous workflows 📃 Skills: C#, .NET, Azure, AWS, Microservices, REST, SOAP, GDS, NDC, Sabre, Amadeus, Travelport, OpenTelemetry, Grafana, ApplicationInsights, APIs, DistributedSystems, Caching, Concurrency, RateLimiting, CircuitBreakers, AsynchronousProcessing 🏢 Description: In Goelett, we are an extraordinary mix of travel industry experts, product, and software engineers, developing a successful online booking tool for corporations and large organizations. Today, as a part of the sector leader S4BT Group, we support 500k+ business users making thousands of bookings a day. We are seeking a Senior.Net Developer / Architect who is keen on working within a product development team, has a background in system and integration analysis, and is ready to take on a dynamic career opportunity by driving requirements analysis, resolving system issues, and enhancing product functionalities! Work model: hybrid (3 days in the office + 2 days remote / weekly) – office located in Warsaw, PL. What you will be doing: Develop clean, scalable code using C# / .NET in a microservices, cloud-native architecture (Azure/AWS). Design and implement high-performance travel search and booking flows (shopping, pricing, availability, ticketing). Integrate with GDS, NDC, LCC APIs. Work with flight and ancillary services including seat maps, baggage, fare families, upsell/cross-sell. Optimize search performance (latency, caching strategies, concurrency, rate limiting, resiliency patterns). Implement orchestration layers for multi-provider search aggregation and normalization of responses. Handle complex pricing logic (fare rules, combinability, branded fares, dynamic pricing). Monitor and optimize system performance, observability (logging, tracing, metrics), and reliability (SLAs/SLOs). Build and maintain scalable APIs (REST/SOAP), event-driven components, and asynchronous workflows. Ensure high availability and fault tolerance in distributed systems (circuit breakers, retries, fallbacks). What we're looking for: 5+ years of professional experience in software development using C# / .NET and modern cloud architectures. 5+ years of travel experience in travel business: flight shopping, booking engines, OTA platforms, or metasearch. Hands-on experience integrating with GDS (Sabre, Amadeus, Travelport) and/or NDC APIs. Solid understanding of airline concepts: PNR, e-ticketing, fare rules, availability, schedule changes, cancellations. Experience with high-throughput, low-latency systems and distributed architectures. Experience with observability tools (e.g., OpenTelemetry, Application Insights, Grafana). Ability to translate business requirements (conversion, pricing accuracy, availability) into technical solutions. What we offer: A truly global perspective – develop your international mindset by collaborating daily with colleagues from diverse cultures and backgrounds across the world. Real impact – contribute to shaping the future of one of the most user-centric companies in the travel-tech industry. Your ideas and solutions will reach thousands of users globally. Medical care – because your well-being matters. Multisport card – keep your body as active as your mind. Extra days off – celebrate your day with a paid day off for your birthday, and another to give back through volunteering. Language courses – grow your communication skills and connect effortlessly in our multicultural environment. Team integrations & fun events. Lunch vouchers – enjoy your breaks with tasty meals on us.

🏢 Summary: Senior Software Engineer role focused on designing and developing scalable, cloud‑native Order management services within a microservice architecture. The position involves advanced backend development in the Java ecosystem, contributing to high‑volume transactional systems used globally. The role combines hands‑on coding, solution design, and technical mentorship in an Agile environment. 🗂️ Requirements: Minimum 5 years of professional software development experience, Advanced programming and solution design skills in Java ecosystem, Strong backend development experience, Solid knowledge of algorithms, data structures, computational complexity, Experience with Google Cloud Platform (GCP), Experience with CI/CD pipelines, Experience with containerization technologies, Experience with cloud‑native architectures, Experience working in Agile environment, Degree in Computer Science or related field or equivalent certifications, Legal work permit in Poland 📃 Skills: Java, GCP, Docker, Kubernetes, CI/CD, Microservices, Algorithms, DataStructures, Cloud, Scrum 🏢 Description: Project info: The Reservation Management team focuses on designing, developing, and maintaining a variety of Order services running on open systems. The team is responsible for Order data distribution to internal and external customers, hosting multiple Order management services, and building an Order data store based on a modern, scalable, microservice-based, cloud-oriented architecture. We use the latest technologies and best engineering practices to handle a high volume of transactions supporting millions of traveling passengers daily. The team operates globally, with the main decision‑driving group located in Kraków, and follows mature Scrum processes. Due to the dynamic growth of the team, we are currently looking for a candidate to join us in the role of Senior Software Engineer. Responsibilities: Develop, code, test, and debug new complex software solutions or enhancements to existing products Design, plan, develop, and improve applications using both routine and advanced technologies Work on complex issues requiring in-depth analysis of organizational objectives; implement strategic policies when selecting methods and techniques Promote high coding standards, best practices, and high-quality deliverables Collaborate regularly with supervisors, architects, product managers, and HR on project-related and team performance topics; influence decision-making in sensitive situations without damaging relationships Provide technical mentorship and competency-based guidance to development teams Share broader business and product context; mentor others on specific tech stacks and technologies Assist in the development of software technical documentation Requirements: Technical Expertise: Advanced programming and solution design skills with deep knowledge of the Java ecosystem Strong experience in advanced backend development and solution design Solid understanding of computer science fundamentals, including algorithms, data structures, and computational complexity Strong knowledge of cloud technologies, particularly Google Cloud Platform (GCP) and related services Familiarity with CI/CD pipelines, containerization technologies (e.g., Docker, Kubernetes), and cloud‑native development Communication & Personal Attributes: Excellent problem-solving and analytical skills Proficient English (written and spoken) Self-disciplined and results-oriented mindset Passion for continuous learning and keeping up to date with industry trends Education & Experience: Minimum 5 years of relevant professional experience Degree in Computer Science or a related field, or equivalent certifications Experience working in a fast-paced, Agile software development environment Must possess a legal work permit in Poland Benefits: General benefits - depends on the form of employment Hybrid working model – 3 selected days per week working from the office Flexible working hours , supporting a healthy work-life balance Attractively located office with collaboration spaces Referral program with financial bonus Life Insurance Budget for development (including language courses and others), clear career path with the possibility to gain experience in international environment Access to internal Learning Platform with multiple trainings oriented for professional growth Lifestyle benefits: Access to MyBenefit platform (Multisport included) Team Building activities Charity initiatives Working environment promoting diversity and inclusion Health benefits: Private medical care - Platinum Package

🏢 Summary: Senior Backend Engineer role focused on building and scaling a cloud-based SaaS platform using modern .NET services and REST APIs. The position involves designing distributed systems, improving reliability and observability, and working with cloud and container environments. You will contribute to technical decisions and engineering best practices within a collaborative team. 🗂️ Requirements: 5+ years backend development experience, Experience with SaaS and web applications, Strong knowledge of C#, Strong knowledge of modern .NET/.NET Core, Solid computer science fundamentals, Experience with distributed systems design, Experience with cloud platforms, Experience with containers and orchestration, Understanding of concurrency and performance, Knowledge of authentication and authorization mechanisms 📃 Skills: C#, .NET, .NETCore, REST, Azure, AWS, GCP, Kubernetes, Kafka, RabbitMQ, SQS, Docker, SQL, HTML, CSS, JavaScript 🏢 Description: We’re hiring a Senior Backend Engineer to help build and scale a cloud-based SaaS platform. You’ll work on modern .NET services and APIs, improve reliability and observability, and contribute to technical decisions as part of a collaborative engineering team. Responsibilities: Build and maintain backend services and REST APIs in C# / .NET (.NET Core). Design scalable solutions for distributed systems (async workflows, messaging, integrations). Work with cloud services (Azure/AWS/GCP) and container environments (e.g. Kubernetes). Strengthen system reliability with logging, metrics, tracing, and monitoring. Support secure access patterns: authentication/authorization, API gateway concepts. Contribute through code reviews, good engineering practices, and automation. Requirements: 5+ years of backend development experience, including SaaS and web applications. Strong knowledge of C# and modern .NET + solid CS fundamentals. Familiarity with containers/orchestration and cloud-native approaches. Experience with some of: Kafka/RabbitMQ/SQS, workflow orchestration, job scheduling, search. Good understanding of concurrency and performance. Strong communication skills; Agile/Scrum is a plus. Bonus: basic front-end knowledge (HTML/CSS/JS).

🏢 Summary: Backend Developer (.NET) role focused on building and migrating a large-scale travel booking platform from monolithic to microservices architecture. The position involves developing scalable backend services, integrating multiple external APIs, and ensuring reliable data synchronization and high-performance booking processes. Work includes close collaboration within Agile teams and contribution to CI/CD practices. 🗂️ Requirements: 3+ years experience with .NET including .NET Core and .NET Framework 4.8 (Web API), Strong knowledge of microservices architecture, Experience with Clean Architecture and MediatR, Solid experience with SQL Server, Solid experience with MongoDB, Experience with Azure Service Bus or NServiceBus, Experience with CI/CD pipelines (preferably Azure DevOps), Ability to work independently and solve complex technical problems, English level Intermediate+ or higher 📃 Skills: .NET, C#, WebAPI, NETCore, SQLServer, MongoDB, Microservices, CleanArchitecture, MediatR, AzureServiceBus, NServiceBus, AzureDevOps, CICD, GitHub, Jira, Confluence 🏢 Description: Andersen is hiring a Backend Developer (.NET) for a project developing a travel platform, ensuring API integrations, data synchronization, and reliable, scalable booking processes. The customer is a technology-driven company in the travel sector, providing a comprehensive booking and procurement platform for industry professionals. Its solutions support large transaction volumes, integrate with a wide network of partners, and offer tools that streamline operations and enhance productivity. Focused on innovation and scalability, the customer continues to expand its ecosystem, strengthen partnerships, and improve data accuracy to deliver a modern digital infrastructure for the travel value chain. The project is focused on developing a travel platform that integrates multiple external APIs into a unified system. It ensures reliable data synchronization and seamless booking processes to support scalable and high-performance partner connectivity. The position assumes 12 to 21 CET work schedule. Responsibilities: Developing and maintaining backend services in .NET 4.8 (Web API) and .NET Core as part of a large-scale migration from monolithic to microservice architecture. Collaborating with cross-functional teams to design and implement scalable, maintainable, and performant services using Clean Architecture and MediatR. Integrating with SQL Server and MongoDB as data backends. Working with Azure Service Bus (NServiceBus) and other Azure services such as Azure Functions and ADF (nice to have). Participating in Agile ceremonies (standups, sprint planning, retrospectives) within 2-week sprint cycles. Contributing to CI/CD practices using Azure DevOps (builds and pipelines). Collaborating via Jira, Confluence, GitHub, and Microsoft Teams. Must-haves: Experience with .NET for 3+ years, including strong experience with .NET Core and .NET Framework 4.8 (Web API). Deep understanding of microservice architecture, Clean Architecture patterns, and MediatR. Solid experience with SQL Server and MongoDB. Experience with Azure Service Bus / NServiceBus. Familiarity with CI/CD tools and pipelines (preferably Azure DevOps). Strong problem-solving skills and the ability to work independently. Level of English – from Intermediate+ and above. Nice-to-haves: Experience in frontend development. Experience with Azure Functions, Azure Data Factory (ADF), or other Azure ecosystem tools. Previous experience in the travel industry, particularly with backend services for hotel booking/search. Reasons why this job would be interesting to you: Experience in teamwork with leaders in FinTech, Healthcare, Retail, Telecom, and others. Andersen cooperates with such businesses as Samsung, Siemens, Johnson & Johnson, BNP Paribas, Ryanair, Mercedes, TUI, Verivox, Allianz, T-Systems, etc.. The opportunity to change the project and/or develop expertise in an interesting business domain. Job conditions – you can work both fully remotely and from the office or can choose a hybrid variant. Guarantee of professional, financial, and career growth! The company has introduced systems of mentoring and adaptation for each new employee. The opportunity to earn up to an additional 1,000 USD per month, depending on the level of expertise, which will be included in the annual bonus, by participating in the company's activities. Access to the corporate training portal, where the entire knowledge base of the company is collected and which is constantly updated. Bright corporate life (parties / pizza days / PlayStation / fruits / coffee / snacks / movies); Certification compensation (AWS, PMP, etc). Referral program. English courses. Private health insurance and compensation for sports activities. Your personal data is protected in accordance with GDPR regulations. Learn more: https://andersenlab.com/privacy-policy Join us!

🏢 Summary: Backend Developer (.NET) role focused on building and migrating a travel platform from monolith to microservices, ensuring reliable API integrations and scalable booking processes. The position involves developing high-performance backend services, integrating multiple external systems, and supporting data synchronization across a distributed architecture. Work includes close collaboration within Agile teams and contribution to CI/CD and cloud-based infrastructure. 🗂️ Requirements: 3+ years experience with .NET, Strong experience with .NET Core, Strong experience with .NET Framework 4.8 (Web API), Experience with microservice architecture, Knowledge of Clean Architecture patterns, Experience with MediatR, Experience with SQL Server, Experience with MongoDB, Experience with Azure Service Bus or NServiceBus, Experience with CI/CD pipelines, Familiarity with Azure DevOps, English level Intermediate+ or higher 📃 Skills: .NET, .NETCore, .NETFramework, WebAPI, Microservices, CleanArchitecture, MediatR, SQLServer, MongoDB, AzureServiceBus, NServiceBus, AzureDevOps, CI/CD, Azure 🏢 Description: Andersen is hiring a Backend Developer (.NET) for a project developing a travel platform, ensuring API integrations, data synchronization, and reliable, scalable booking processes. The customer is a technology-driven company in the travel sector, providing a comprehensive booking and procurement platform for industry professionals. Its solutions support large transaction volumes, integrate with a wide network of partners, and offer tools that streamline operations and enhance productivity. Focused on innovation and scalability, the customer continues to expand its ecosystem, strengthen partnerships, and improve data accuracy to deliver a modern digital infrastructure for the travel value chain. The project is focused on developing a travel platform that integrates multiple external APIs into a unified system. It ensures reliable data synchronization and seamless booking processes to support scalable and high-performance partner connectivity. The position assumes 12 to 21 CET work schedule. Responsibilities: Developing and maintaining backend services in .NET 4.8 (Web API) and .NET Core as part of a large-scale migration from monolithic to microservice architecture. Collaborating with cross-functional teams to design and implement scalable, maintainable, and performant services using Clean Architecture and MediatR. Integrating with SQL Server and MongoDB as data backends. Working with Azure Service Bus (NServiceBus) and other Azure services such as Azure Functions and ADF (nice to have). Participating in Agile ceremonies (standups, sprint planning, retrospectives) within 2-week sprint cycles. Contributing to CI/CD practices using Azure DevOps (builds and pipelines). Collaborating via Jira, Confluence, GitHub, and Microsoft Teams. Must-haves: Experience with .NET for 3+ years, including strong experience with .NET Core and .NET Framework 4.8 (Web API). Deep understanding of microservice architecture, Clean Architecture patterns, and MediatR. Solid experience with SQL Server and MongoDB. Experience with Azure Service Bus / NServiceBus. Familiarity with CI/CD tools and pipelines (preferably Azure DevOps). Strong problem-solving skills and the ability to work independently. Level of English – from Intermediate+ and above. Nice-to-haves: Experience in frontend development. Experience with Azure Functions, Azure Data Factory (ADF), or other Azure ecosystem tools. Previous experience in the travel industry, particularly with backend services for hotel booking/search. Reasons why this job would be interesting to you: Experience in teamwork with leaders in FinTech, Healthcare, Retail, Telecom, and others. Andersen cooperates with such businesses as Samsung, Siemens, Johnson & Johnson, BNP Paribas, Ryanair, Mercedes, TUI, Verivox, Allianz, T-Systems, etc.. The opportunity to change the project and/or develop expertise in an interesting business domain. Job conditions – you can work both fully remotely and from the office or can choose a hybrid variant. Guarantee of professional, financial, and career growth! The company has introduced systems of mentoring and adaptation for each new employee. The opportunity to earn up to an additional 1,000 USD per month, depending on the level of expertise, which will be included in the annual bonus, by participating in the company's activities. Access to the corporate training portal, where the entire knowledge base of the company is collected and which is constantly updated. Bright corporate life (parties / pizza days / PlayStation / fruits / coffee / snacks / movies); Certification compensation (AWS, PMP, etc). Referral program. English courses. Private health insurance and compensation for sports activities. Your personal data is protected in accordance with GDPR regulations. Learn more: https://andersenlab.com/privacy-policy Join us!