Senior .NET (Web) (m/f/n)

🏢 Summary: Freelance, part-time .NET Developer role focused on 2nd line support in a 24/7 on-call model for maintaining and troubleshooting existing applications. The position involves analyzing incidents, fixing bugs, and ensuring stability and performance of .NET systems. Work is remote, ticket-based, and coordinated in advance within a technical team. 🗂️ Requirements: Minimum 3 years of experience in .NET backend development, Proficiency in C#, Experience with ASP.NET Core API, Experience with Entity Framework Core, Experience with SQL Server, Experience with Docker, Experience with Redis, Experience with asynchronous communication (e.g. RabbitMQ), Experience with unit testing frameworks (e.g. xUnit), Availability for rotational 24/7 on-call duties 📃 Skills: .NET, C#, ASP.NET, EntityFramework, SQL, SQLServer, Docker, Redis, RabbitMQ, xUnit, REST 🏢 Description: Work Mode: Freelance / Part-time Location: Remote Cooperation Model: Flexible (standby / on-call duties) We are looking for a .NET Developer to support second-line support (2nd line) in one of our projects. The role is based on an on-call / standby model , with schedules planned in advance together with the team. Tickets are assigned after initial analysis on the client’s side – this is not 1st line support nor a call center . The team consists of developers and a coordinator (PM). Project 24/7 on-call duty Responsibilities Handling service requests (2nd line support) Analyzing and diagnosing issues in .NET applications Bug fixing in existing codebases Working with REST APIs Collaboration with other developers (backend, frontend, mobile) Testing the correctness of implemented fixes Direct communication with the client regarding reported issues Work Model No fixed number of working hours Flexible model based on rotational on-call duties On-call schedules planned in advance together with you Clear communication of availability and ticket acceptance is essential Compensation Standby / On-call: 180 PLN per weekday (24h) 250 PLN per weekend day (24h)➕ Hourly rate for actual work performed Requirements Min. 5 years of experience in .NET backend development Good proficiency in C#, ASP.NET Core API, and Entity Framework Core Experience with SQL Server, Docker, and Redis Familiarity with asynchronous communication (RabbitMQ or similar) Experience with unit testing frameworks (xUnit or similar) Strong problem-solving skills and focus on performance and scalability Availability for on-call work Nice to Have Experience in 2nd / 3rd line support Experience with high-availability systems (SLA, on-call) Knowledge of monitoring and logging tools Experience in direct communication with clients We value your trust in providing us your data, thus we are striving to use commercially acceptable means of protecting it. Below you will find the necessary information about the data we collect and process when you send us your CV. The controller of your personal data is Miquido Spółka z ograniczoną odpowiedzialnością sp. k. with its seat in Krakow, Zabłocie 43a, 30-701 Kraków, Poland (“Miquido”, “We”, “Our” or “Us”). See more

🏢 Summary: Senior .NET Developer role focused on building and architecting cloud-native backend systems with AWS and CI/CD automation. The position involves designing microservices-based solutions, writing high-quality testable code, and contributing across the full project lifecycle in a spec-driven environment. Fully remote B2B contract with long-term cooperation potential. 🗂️ Requirements: Experience with modern .NET / .NET Core, Experience with AWS or Azure, Knowledge of microservices architecture, Knowledge of distributed systems, Ability to design system architecture, Experience writing integration tests, Experience writing end-to-end tests, Familiarity with BDD approach, Experience with CI/CD automation 📃 Skills: .NET, NETCore, AWS, Azure, CI/CD, Microservices, DistributedSystems, C#, BDD, IntegrationTesting, E2ETesting, Architecture 🏢 Description: Join an international IT company specializing in cloud services, managed services, and digital transformation for enterprises. As a Senior .NET Developer with a focus on AWS and CI/CD automation, you will participate in the project by providing backend support to the Tech Lead and a team. Key responsibilities Designing and architecting system components, Writing high-quality, testable code in .NET, Contributing to the development of modern cloud-native solutions, Working across the full project lifecycle (from discovery to delivery), Participating in planning and analysis (discovery, planning), Working in a “spec-driven” approach (based on specifications), Co-creating and refining specifications, acceptance criteria, and architectural decisions. Ideal candidate profile Experience with . NET (Core / modern .NET), Azure or AWS , Knowledge of architecture: microservices, distributed systems, Ability to translate business requirements into technical architecture, Writing integration and end-to-end tests, Familiarity with BDD (Behavior-Driven Development) approach. Conditions Type of cooperation: B2B contract Initial contract duration: 1st June- End of February 2027, with the intention to extend the cooperation or move top performers to another project. Rate: 130 - 160 PLN/h Benefits: Private healthcare, Multisport card and life insurance Work model: 100% remote from any location in Poland Recruitment steps Phone call with a Recruiter - Oliwia (approx. 20 min.) Interview with Client : Introductory conversation with the delivery team: review of your experience vs project needs, light technical questions, and verification of your comfort in a fully English‑speaking, international environment. Introductory interview : discussion of experience in relation to project requirements, technical questions. Final technical interview with Client : in‑depth technical questions, possibly practical task to see how you think, ask questions, and structure solutions. Decision and feedback

🏢 Summary: 100% remote B2B opportunity to lead a development team in building and maintaining scalable applications within an agile environment. The role combines hands-on full-stack development with strategic technical leadership, focusing on robust system architecture and faster delivery of new solutions. Long-term cooperation with a two-stage recruitment process including a technical test. 🗂️ Requirements: Proficiency in .NET, Proficiency in C#, Experience in full-stack development, Experience with front-end technologies, Experience with document-based databases, Knowledge of event-based messaging frameworks, Experience with cloud services, Experience with containerization, Ability to lead development teams, Experience working in agile environment 📃 Skills: .NET, C#, Angular, MongoDB, Cloud, Docker, Microservices, REST, Git 🏢 Description: Work model: 100% remote Start date: Flexible Rate: up to 215 PLN/h netto + VAT Contract : B2B, long-term cooperation (12-month contract up front + extensions) Recruitment process : 2 stages, including a technical test estimated to take 2-4 hours. Summary: The role focuses on leading the development team to create new solutions and maintain systems within an agile environment, emphasizing the importance of robust applications and strategic direction. Main Responsibilities: Lead the development team in creating and maintaining applications. Adopt wider technology practices and address the speed of new application delivery. Engage in hands-on development while guiding the strategic direction of projects. Collaborate with teams to gather specifications and perform technical analysis. Navigate complex systems and ensure they are built to scale. Manage developer quality and capacity amidst organizational constraints. Key Requirements: Proficient in .NET and C#. Experience with full-stack development, including front-end technologies. Familiarity with document-based databases. Knowledge of event-based messaging frameworks. Experience with cloud services and containerization. Nice to Have: Prior experience in the banking or financial services sector. Familiarity with Angular or other modern front-end frameworks. Experience with MongoDB or similar environments. Other Details: Environment: .NET, C#, Angular, MongoDB, moving towards cloud solutions. Team Structure: Full Stack Developers working closely with Business Analysts.

🏢 Summary: Long-term remote B2B contract for a technical leader responsible for guiding a development team in building and maintaining scalable applications within an agile environment. The role combines hands-on .NET development with strategic oversight, technical analysis, and quality management. Focus is on delivering robust, cloud-oriented solutions and improving application delivery speed. 🗂️ Requirements: Proficiency in .NET and C#, Experience in full-stack development, Experience with front-end technologies, Experience with document-based databases, Knowledge of event-based messaging frameworks, Experience with cloud services, Experience with containerization, Ability to lead development team, Experience in building scalable systems 📃 Skills: .NET, C#, Angular, MongoDB, Cloud, Docker, Messaging, SQL 🏢 Description: Work model: 100% remote Start date: 30.06.2026 Rate: 160-180 PLN/h netto + VAT Contract : B2B, long-term cooperation (12-month contract up front + extensions) Recruitment process : 2 stages, including a technical test estimated to take 2-4 hours. Summary: The role focuses on leading the development team to create new solutions and maintain systems within an agile environment, emphasizing the importance of robust applications and strategic direction. Main Responsibilities: Lead the development team in creating and maintaining applications. Adopt wider technology practices and address the speed of new application delivery. Engage in hands-on development while guiding the strategic direction of projects. Collaborate with teams to gather specifications and perform technical analysis. Navigate complex systems and ensure they are built to scale. Manage developer quality and capacity amidst organizational constraints. Key Requirements: Proficient in .NET and C#. Experience with full-stack development, including front-end technologies. Familiarity with document-based databases. Knowledge of event-based messaging frameworks. Experience with cloud services and containerization. Nice to Have: Prior experience in the banking or financial services sector. Familiarity with Angular or other modern front-end frameworks. Experience with MongoDB or similar environments. Other Details: Environment: .NET, C#, Angular, MongoDB, moving towards cloud solutions. Team Structure: Full Stack Developers working closely with Business Analysts.

🏢 Summary: Technical leadership role focused on driving the development and maintenance of scalable .NET-based applications in an agile environment. The position combines hands-on full-stack development with strategic oversight of architecture, quality, and delivery speed. It involves close collaboration with cross-functional teams to build robust, cloud-oriented solutions. 🗂️ Requirements: Proficiency in .NET and C#, Experience in full-stack development, Knowledge of front-end technologies, Experience with document-based databases, Knowledge of event-based messaging frameworks, Experience with cloud services, Experience with containerization, Ability to design scalable systems, Experience leading development teams 📃 Skills: .NET, C#, Angular, MongoDB, Cloud, Docker, Kubernetes, Microservices, REST, Git 🏢 Description: Work model: 100% remote Start date: 30.06.2026 Rate: 160-180 PLN/h netto + VAT Contract : B2B, long-term cooperation (12-month contract up front + extensions) Recruitment process : 2 stages, including a technical test estimated to take 2-4 hours. Summary: The role focuses on leading the development team to create new solutions and maintain systems within an agile environment, emphasizing the importance of robust applications and strategic direction. Main Responsibilities: Lead the development team in creating and maintaining applications. Adopt wider technology practices and address the speed of new application delivery. Engage in hands-on development while guiding the strategic direction of projects. Collaborate with teams to gather specifications and perform technical analysis. Navigate complex systems and ensure they are built to scale. Manage developer quality and capacity amidst organizational constraints. Key Requirements: Proficient in .NET and C#. Experience with full-stack development, including front-end technologies. Familiarity with document-based databases. Knowledge of event-based messaging frameworks. Experience with cloud services and containerization. Nice to Have: Prior experience in the banking or financial services sector. Familiarity with Angular or other modern front-end frameworks. Experience with MongoDB or similar environments. Other Details: Environment: .NET, C#, Angular, MongoDB, moving towards cloud solutions. Team Structure: Full Stack Developers working closely with Business Analysts.

🏢 Summary: Senior .NET Developer role focused on designing, extending, and modernising critical banking and securities systems in a fully remote B2B model. The position involves full-stack development, system integration, and cloud scaling within distributed, business-critical environments. The role requires close collaboration with business stakeholders and ownership of end-to-end application delivery. 🗂️ Requirements: 5+ years experience as .NET / C# Developer, Experience in banking or investment banking sector, Full-stack development experience, Knowledge of SOLID design principles, Experience with document-based databases, Experience with event-driven messaging frameworks, Experience with unit and integration testing, End-to-end application development experience, Ability to work during UK business hours, Based in Poland 📃 Skills: .NET, C#, MongoDB, SOLID, Messaging, UnitTesting, IntegrationTesting, Docker, Kubernetes, Cloud 🏢 Description: Work model: 100% remote (candidates must be based in Poland) Contract type: B2B Industry: Banking / Investment Banking We are looking for an experienced Senior .NET Developer to join a distributed engineering team working on critical banking systems. The role focuses on extending and modernising applications used across securities and banking operations, with a strong emphasis on system design, scalability, and cloud transformation. You will work end-to-end on business-critical systems, closely collaborating with Business Analysts, without a separate QA team. A solid background in banking or financial services is essential. Main Responsibilities: Design, develop, and extend .NET-based systems supporting multiple banking entities Contribute to the integration of securities and core banking platforms Support and enhance a portfolio of ~17 applications across product control and risk management Work with an in-house development framework in a full-stack capacity Participate in scaling applications for cloud-based, containerized environments Collaborate closely with business stakeholders to deliver robust solutions Ensure high code quality through unit and integration testing Key Requirements: 5+ years of professional experience as a .NET / C# Developer Hands-on experience in the banking or investment banking sector (mandatory) Full-stack development experience (backend-focused, frontend included) Strong understanding and practical application of SOLID design principles Experience with document-based databases (e.g. MongoDB) Experience with event-driven / event-based messaging frameworks Solid knowledge of unit and integration testing Experience working end-to-end on applications (development, testing, support) Ability to work independently in a fast-paced, regulated environment Availability during UK business hours Nice to Have: Experience with cloud platforms and application migration to cloud Experience with container technologies (e.g. Docker, Kubernetes) Exposure to systems such as Murex or large in-house banking platforms Background in securities, risk, or product control systems Other Details: This role is 100% remote with candidates required to be located in Poland. The contract is on a B2B basis within the banking and investment banking industry.

🏢 Summary: Senior .NET Developer role focused on designing, extending, and modernizing critical banking systems within securities and core banking domains. The position involves full-stack development, system integration, and cloud scaling in a distributed team without a separate QA function. Work includes end-to-end ownership of business-critical applications in a regulated investment banking environment. 🗂️ Requirements: 5+ years experience with .NET and C#, Hands-on experience in banking or investment banking, Full-stack development experience, Strong knowledge of SOLID principles, Experience with document-based databases, Experience with event-driven messaging frameworks, Knowledge of unit and integration testing, End-to-end application development experience, Ability to work independently in regulated environments, Availability during UK business hours, Poland-based residency 📃 Skills: .NET, C#, MongoDB, SQL, REST, Microservices, Docker, Kubernetes, Azure, UnitTesting, IntegrationTesting, EventDriven, Git 🏢 Description: Work model: 100% remote (candidates must be based in Poland) Contract type: B2B Industry: Banking / Investment Banking We are looking for an experienced Senior .NET Developer to join a distributed engineering team working on critical banking systems. The role focuses on extending and modernising applications used across securities and banking operations, with a strong emphasis on system design, scalability, and cloud transformation. You will work end-to-end on business-critical systems, closely collaborating with Business Analysts, without a separate QA team. A solid background in banking or financial services is essential. Main Responsibilities: Design, develop, and extend .NET-based systems supporting multiple banking entities Contribute to the integration of securities and core banking platforms Support and enhance a portfolio of ~17 applications across product control and risk management Work with an in-house development framework in a full-stack capacity Participate in scaling applications for cloud-based, containerized environments Collaborate closely with business stakeholders to deliver robust solutions Ensure high code quality through unit and integration testing Key Requirements: 5+ years of professional experience as a .NET / C# Developer Hands-on experience in the banking or investment banking sector (mandatory) Full-stack development experience (backend-focused, frontend included) Strong understanding and practical application of SOLID design principles Experience with document-based databases (e.g. MongoDB) Experience with event-driven / event-based messaging frameworks Solid knowledge of unit and integration testing Experience working end-to-end on applications (development, testing, support) Ability to work independently in a fast-paced, regulated environment Availability during UK business hours Nice to Have: Experience with cloud platforms and application migration to cloud Experience with container technologies (e.g. Docker, Kubernetes) Exposure to systems such as Murex or large in-house banking platforms Background in securities, risk, or product control systems Other Details: This role is 100% remote with candidates required to be located in Poland. The contract is on a B2B basis within the banking and investment banking industry.

🏢 Summary: Full Stack Development Lead role focused on delivering end-to-end solutions using React and C# .NET Core in a cloud-driven, microservices-based environment. The position combines hands-on development with architectural input and technical leadership in a fully remote B2B setup. The role involves close collaboration with cross-functional teams and contribution to modern DevOps and data workflows. 🗂️ Requirements: Proven full-stack experience with React, TypeScript, C# .NET Core, Strong knowledge of microservices architecture, Understanding of distributed systems, Experience with CI/CD pipelines, Experience with cloud platforms (Azure preferred), Experience with containers, Familiarity with DevOps practices, Ability to design APIs and event-driven components 📃 Skills: React, TypeScript, C#, .NET, Microservices, CI/CD, Azure, Docker, DevOps, PySpark, PowerBI, APIs 🏢 Description: Start Date: ASAP / Within 1 Month / Flexible Work Model: 100% remote Contract Type: B2B (160-180 PLN/h + VAT) We are looking for an experienced Full Stack Development Lead who will take ownership of end‑to‑end solutions across React and C# .NET Core while contributing to technical direction and supporting a collaborative engineering culture. This role is ideal for a strong Senior Full Stack Developer who is ready to expand into leadership responsibilities, work closely with cross‑functional teams, and influence architectural decisions in a modern, cloud‑driven environment. Expectations Proven experience in full‑stack development using React, TypeScript, and C# .NET Core. Good understanding of microservices , distributed systems, and CI/CD pipelines. Exposure to cloud platforms (Azure preferred), containers, and modern DevOps practices. Experience with data workflows (pyspark) or BI solutions (Power BI) is a strong advantage. Ability to collaborate with technical and business stakeholders and take initiative in solution design. Responsibilities Contribute to the design and delivery of full‑stack applications using React and C# .NET Core. Support architectural discussions around microservices, APIs, and event‑driven components. Collaborate with data engineers on pyspark workflows and Power BI reporting enhancements. Promote engineering best practices, code quality, and maintainable development patterns. Mentor team members and support planning, collaboration, and continuous improvement efforts. What We Offer Medicover healthcare package Multisport card Access to an e-learning platform Group life insurance

🏢 Summary: Lead .NET Engineer role combining hands-on backend development with technical leadership, owning architecture, core platform services, APIs, and payment integrations in a distributed AWS environment. The position includes defining technical direction, mentoring engineers, driving CI/CD and operational excellence, and promoting AI-assisted development practices. After a short onboarding period in the US, the role is fully remote with long-term engagement in a strategic product initiative. 🗂️ Requirements: 6–10+ years of experience building and operating production software systems, Experience in Technical Lead or Lead Engineer role, Strong backend development experience with C# and .NET, Experience designing and operating distributed systems and microservices, Strong SQL and database design skills, Hands-on experience with AWS (SQS, DynamoDB, S3, ECS, Lambda), Experience owning and improving CI/CD pipelines, Experience in payments, financial services, or regulated environments, Working knowledge of React or Vue 📃 Skills: C#, .NET, AWS, ECS, Lambda, SQS, DynamoDB, S3, SQL, Microservices, REST, CI/CD, React, Vue, AI 🏢 Description: Lead .NET Engineer Remote 140–160 PLN/h B2B Full-time (FTE) *Project starts with a 2–3 week onboarding and training period in the US, followed by fully remote work. About the role We are looking for an experienced Lead .NET Engineer to take ownership of a squad responsible for core platform services, APIs, and payment integrations. In this role, you will combine hands-on software engineering with technical leadership. You will define technical direction, partner with Product on roadmap delivery, mentor engineers, and help drive the adoption of AI-assisted development practices across the software delivery lifecycle. Responsibilities Own squad-level architecture and technical decision-making. Lead the design, development, and operation of backend services and APIs. Ensure high standards of code quality, performance, security, and reliability. Drive incident management and operational excellence. Collaborate closely with Product Managers and stakeholders to deliver roadmap priorities. Mentor engineers through coaching, technical guidance, and regular feedback. Participate in hiring and team growth activities. Promote and implement AI-assisted development tools and best practices. Contribute to continuous improvement of engineering processes, CI/CD, and platform capabilities. Must-have requirements 6–10+ years of experience building and operating production software systems. Proven experience in a Technical Lead, Lead Engineer, or similar leadership role. Strong backend development experience with C#/.NET. Working knowledge of frontend technologies such as React or Vue. Experience designing and operating distributed systems and microservice architectures. Strong SQL and database design skills. Experience working within payments, financial services, or other regulated environments. Hands-on experience with AWS services, including: SQS DynamoDB S3 ECS Lambda Experience owning and improving CI/CD pipelines. Strong communication and stakeholder management skills. Nice to have Experience building large-scale payment platforms or fintech products. Previous people-management responsibilities. Experience with platform modernization and cloud transformation initiatives. Experience implementing AI-powered engineering tools and workflows. Tech Stack C# .NET AWS ECS Lambda SQS DynamoDB S3 SQL Microservices REST APIs CI/CD React / Vue AI-assisted Development What we offer Long-term engagement in a strategic product initiative. High-impact technical leadership role. Opportunity to shape engineering standards and architecture. Exposure to modern AI-assisted development practices. International environment and collaboration with US-based teams. Fully remote work after onboarding period in the US.

🏢 Summary: Full-time B2B contract for a .NET Developer to maintain and enhance an existing self-service portal based on legacy ASP.NET Web Forms. The role focuses on stabilizing, hosting, and gradually developing new features in a poorly documented codebase. The project runs until the end of 2026 with possible extensions and is fully remote. 🗂️ Requirements: Proficiency in ASP.NET Web Forms and classic .NET, Experience with IIS hosting and configuration, Strong understanding of legacy authentication methods, Ability to work with and stabilize poorly documented codebases, Experience maintaining and supporting existing web applications 📃 Skills: ASP.NET, WebForms, .NET, IIS, Authentication, SQL, T-SQL, MS SQL 🏢 Description: Industry: debt collection Remote work: 100% Project language: English FTE: full-time (if you're interested in part-time, it's also ok) Project length: until the end of 2026 + prolongations Start: ASAP Assignment type: B2B Remuneration: up to 180 PLN/h Job Summary: The .NET Developer will be primarily responsible for maintaining and developing an existing self-service portal used by customers and clients, which incorporates legacy code as well as newer components. Responsibilities: Maintain and stabilize an existing ASP.NET application, ensuring uptime and functionality. Perform IIS hosting and configuration for the application. Understand legacy authentication patterns to facilitate secure access. Work with poorly documented codebases, improving clarity and stability. Periodically develop new features as required by the project. Must Haves: Proficient in ASP.NET Web Forms / classic .NET technology (e.g., client_login.aspx). Experience with IIS hosting and configuration. Strong understanding of legacy authentication methods. Ability to read and stabilize poorly documented codebases. Nice to Have: Familiarity with newer development practices and components (e.g., ASP.NET MVC Core). Experience with MS SQL, including queries and stored procedures. Knowledge of application maintenance workflows.