June 20, 2026

.NET Backend Developer

Senior • Remote

140 - 180 PLN/hr

Warsaw, Poland

For our client from the technology and industrial solutions sector, we are looking for a .NET Back-End Developer to join a talented development team working on modern, scalable software solutions.

Responsibilities:

  • Design, develop, and maintain high-performance back-end services using .NET and C#.

  • Work extensively with Azure cloud services and CosmosDB to build scalable and resilient solutions.

  • Collaborate with front-end developers, product owners, and other team members to integrate back-end services.

  • Participate in code reviews, architectural discussions, sprint planning, and other Agile ceremonies.

  • Use modern development tools and practices to improve productivity, code quality, and maintainability.

  • Explore and apply AI-assisted tools where appropriate to support development, documentation, troubleshooting, and workflow efficiency.

  • Contribute to improving development processes, engineering practices, and team knowledge sharing.

  • Be a proactive problem-solver and continuous learner, staying current with relevant technologies and industry trends.

Requirements:

  • Application Development Experience: 5+ years of professional experience in .NET development.

  • Cloud Development Expertise: Proven experience with C#, Azure services, and CosmosDB.

  • Scripting / Front-End Knowledge: Experience with TypeScript preferred, or JavaScript.

  • AI Tool Familiarity: Interest in or hands-on experience using AI tools to support software development, productivity, documentation, research, or troubleshooting.

  • Educational Background: Bachelor’s degree in Computer Science or a related field.

  • Flexibility: Ability to align somewhat with US-based team working hours.

  • Communication: English language proficiency.

 

Stack:

  • Cloud: Azure, CosmosDB

  • Back-End: .NET, C#

  • Scripting / Tooling: TypeScript preferred, JavaScript acceptable

  • Productivity / AI Tools: Familiarity with AI-assisted development or productivity tools is a plus

Nice to have:

  • Domain Knowledge: Background in Electrical Engineering or a related technical field.

  • Background or interest in analog and mixed-signal hardware design.

  • Knowledge of hardware or system simulation concepts.

  • CMS Knowledge: Familiarity with Drupal.

  • Test Automation Exposure: Familiarity with tools like Playwright or Selenium.

  • Quality Mindset: Prior QA experience or understanding of QA methodologies is welcome.

Offer:

 

  • Cooperation based on a B2B contract and rate: 140-170 PLN/hour

  • 100% remote work 

  • The support of a dedicated mentor. In the relationship, we focus on direct communication. When you join speedapp, you will be put in touch with a dedicated mentor who will make sure that you enjoy working with us and with the client.

  • Events and integration meetings, as well as participation in various initiatives, e.g., sports.

  • Access to the benefits offering (medical care, Multisport card).

 

About Speedapp

At speedapp, we believe that an organization is only as good as the people who make it up. We are a team of IT experts and other professionals working for our clients around the world (including Israel, Austria, USA). We go far beyond the HR category. We build IT teams and also help manage them.

👉 10 years of experience

👉 +100 clients worldwide 

+300 hires per year

💎 We have won the prestigious "Forbes Diamonds" award four times (2022, 2023, 2024, 2025). We are a member of the European Fast Growth Icons network and FinTech Poland. We are ranked 18th among the 100 fastest growing companies 2023 by Clutch.

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Warsaw, Poland

90 - 120 PLN

🏢 Summary: Offer for a .NET Backend Developer focused on building backend services in a microservices and cloud-native environment. The role includes developing REST APIs, API-to-API integrations, data access layers, and collaborating in Scrum teams using modern backend technologies. 🗂️ Requirements: Experience as .NET Backend Developer, Practical knowledge of .NET, Knowledge of Scrum, Practical knowledge of Git, Experience with API-to-API communication, Knowledge of asynchronous programming, Experience designing and implementing REST API, Practical knowledge of Entity Framework, Good knowledge of SQL, Experience with PostgreSQL, Experience with microservices architecture, Knowledge of Cloud Native solutions 📃 Skills: .NET, Scrum, Git, REST, EntityFramework, SQL, PostgreSQL, Microservices, CloudNative, Async, API, AWS, Kubernetes, KQL, SIEM, Elastic, Hangfire, gRPC, GraphQL 🏢 Description: O projekcie Poszukujemy .NET Backend Developera do realizacji projektów opartych o architekturę mikroserwisową i rozwiązania cloud-native. Rola obejmuje rozwój usług backendowych, integrację systemów poprzez API oraz współpracę z zespołem projektowym zgodnie z metodyką Scrum. Twój zakres obowiązków projektowanie i rozwój aplikacji backendowych w technologii .NET implementacja oraz rozwój mikroserwisów tworzenie i rozwój REST API integracja systemów z wykorzystaniem komunikacji API-to-API projektowanie i rozwój rozwiązań opartych o architekturę cloud-native współpraca z zespołem projektowym w metodyce Scrum rozwój oraz utrzymanie warstwy dostępu do danych udział w przeglądach kodu oraz stosowanie dobrych praktyk programistycznych Nasze wymagania doświadczenie jako .NET Backend Developer praktyczna znajomość .NET znajomość metodyki Scrum praktyczna znajomość Git doświadczenie w komunikacji API-to-API znajomość programowania asynchronicznego (Async) doświadczenie w projektowaniu i implementacji REST API praktyczna znajomość Entity Framework dobra znajomość SQL doświadczenie z PostgreSQL doświadczenie w pracy z architekturą mikroserwisową znajomość rozwiązań Cloud Native Mile widziane znajomość AWS doświadczenie z Kubernetes znajomość KQL doświadczenie z SIEM znajomość Elastic znajomość Hangfire doświadczenie z gRPC znajomość GraphQL

Technology

speedapp

Senior Node.js Developer

Senior

Remote

Warsaw, Poland

27,000 - 27,000 PLN

🏢 Summary: Backend Developer role focused on building and maintaining scalable microservices-based web platforms for international projects. The position involves designing and developing high-performance REST APIs, implementing new features, optimizing application performance, and ensuring code quality through testing and reviews. The engineer will have real impact on system architecture and technical direction. 🗂️ Requirements: Minimum 5 years commercial experience with Node.js, Strong knowledge of Express.js, Strong knowledge of NestJS, Solid knowledge of TypeScript, Experience with SQL databases, Experience with ORM tools (e.g. TypeORM), Experience designing and implementing REST API, Knowledge of SOLID principles and design patterns, Experience with unit and E2E testing (e.g. Jest), Proficiency with Git, Experience with Docker and containerization, Experience with microservices architecture, English level B2 or higher 📃 Skills: Node.js, Express.js, NestJS, TypeScript, SQL, TypeORM, REST, SOLID, Jest, Git, Docker, Microservices, AWS, Azure, GCP, Prometheus, Grafana, ELK, CI/CD, GitLabCI, GitHubActions, Jenkins, GraphQL 🏢 Description: Dołącz do zespołu klienta z branży technologicznej i twórz nowoczesne, skalowalne rozwiązania backendowe wykorzystywane w projektach o międzynarodowym zasięgu. Będziesz mieć realny wpływ na architekturę systemów oraz kierunek ich dalszego rozwoju. ZADANIA Rozwój i utrzymanie backendu platformy webowej opartej o architekturę mikroserwisową, której celem jest zapewnienie wysokiej wydajności, stabilności i skalowalności. Praca nad usługami obsługującymi dużą liczbę użytkowników z różnych krajów. Projektowanie i rozwijanie REST API. Implementacja nowych funkcjonalności zgodnie z wymaganiami biznesowymi i technicznymi. Utrzymanie istniejącego kodu, debugowanie oraz rozwiązywanie problemów produkcyjnych. Monitorowanie wydajności aplikacji i optymalizacja jej działania. Tworzenie i utrzymywanie testów jednostkowych oraz end-to-end. Udział w code review i dbanie o wysoką jakość kodu. Tworzenie i aktualizacja dokumentacji technicznej. Aktywny udział w spotkaniach zespołowych (daily, planowanie, refinement). Wsparcie zespołu w estymacjach projektowych i działaniach biznesowych. Mentoring młodszych programistów i dzielenie się wiedzą. WYMAGANIA Minimum 5 lat komercyjnego doświadczenia w tworzeniu aplikacji backendowych z wykorzystaniem Node.js . Bardzo dobra znajomość frameworków Express.js oraz NestJS . Solidna znajomość TypeScript . Doświadczenie w pracy z bazami danych SQL oraz ORM (np. TypeORM ). Praktyczne doświadczenie w projektowaniu i implementacji REST API . Znajomość zasad SOLID i wzorców projektowych. Doświadczenie w pisaniu testów jednostkowych i E2E (np. Jest ). Dobra znajomość GIT jako systemu kontroli wersji. Doświadczenie w pracy z Dockerem i konteneryzacją aplikacji. Znajomość architektury mikroserwisowej i doświadczenie w projektach opartych o mikroserwisy. Umiejętność pracy zespołowej, komunikatywność i otwartość na feedback. Samodzielność, proaktywność oraz chęć rozwoju i podnoszenia kwalifikacji. Znajomość języka angielskiego na poziomie minimum B2 . Wykształcenie wyższe techniczne (informatyka lub pokrewne) będzie dodatkowym atutem. MILE WIDZIANE Doświadczenie w pracy z chmurą (AWS, Azure, GCP). Znajomość narzędzi do monitoringu i obserwowalności (np. Prometheus, Grafana, ELK). Doświadczenie z CI/CD (GitLab CI, GitHub Actions, Jenkins). Znajomość GraphQL. Doświadczenie w pracy w projektach o dużej skali i wysokiej dostępności (high availability). Doświadczenie w branżach takich jak fintech, e-commerce, healthcare lub SaaS. CO OFERUJEMY NA TYM PROJEKCIE? Współpracę w oparciu o umowę B2B. Pracę 100% zdalną. Wsparcie dedykowanego opiekuna. Po dołączeniu do speedapp, otrzymasz kontakt do dedykowanego opiekuna, który zadba, aby współpraca z nami oraz z klientem sprawiała Ci satysfakcję. Wydarzenia oraz spotkania integracyjne, a także udział w różnych inicjatywach np. sportowych. Dostęp do oferty benefitów (opieka medyczna, ubezpieczenie na życie, karta Multisport). JAK WYGLĄDA REKRUTACJA? Zgłoszenie: Zaaplikuj i prześlij swoje CV. Po weryfikacji aplikacji rekruter skontaktuje się telefonicznie z wybranymi kandydatami. Screening: Porozmawiaj z rekruterem speedapp o Twoim doświadczeniu. Kolejne etapy: Rekruter speedapp przedstawi Ci jak wygląda proces rekrutacji na dane stanowisko. Rekruter speedapp pozostanie z Tobą w kontakcie podczas całego procesu. O SPEEDAPP W speedapp wierzymy, że organizacja jest tak dobra jak tworzący ją ludzie. Jesteśmy zespołem ekspertów IT i innych specjalistów pracujących dla naszych klientów na całym świecie (m.in Izrael, Austria, USA). Wykraczamy daleko poza kategorię HR. Budujemy zespoły IT, a także pomagamy w ich zarządzaniu. 👉 10 lat doświadczenia 👉 +100 klientów na całym świecie +300 zatrudnień rocznie 💎 Jesteśmy laureatem prestiżowej nagrody Diamenty Forbes cztery lata z rzędu (2022, 2023, 2024, 2025), członkiem sieci Fast Growth Icons oraz FinTech Poland. MASZ PYTANIA? Skontaktuj się bezpośrednio z rekruterem odpowiedzialnym za ten proces. Adrianna RudzkaJunior IT Delivery Consultantadrianna.rudzka@speedapp.pl +48 884 271 647