Regular .NET Developer (Card Payment Systems)

MARGO; Województwo mazowieckie; Hybrid; PLN 180,000 - 240,000; Full time

Job summary

A leading technology firm is seeking a Regular .NET Developer to work remotely while maintaining core card payment systems. This role involves developing applications, optimizing performance, and collaborating within Agile teams. Candidates should have strong skills in C#, .NET, and system integrations, with Polish at a native level. Benefits include B2B cooperation, medical care, and training support. Hourly rates are between 100 zł and 110 zł.

Benefits

Medical care

Sports card

Training and certification support

International project involvement

Integration events

Qualifications

• Commercial experience with C# and .NET is required.
• Experience with system integrations using REST and SOAP.
• Knowledge of SOLID principles and design patterns.

Responsibilities

• Develop and maintain .NET applications in the card payment domain.
• Participate in Agile/Scrum teams and code reviews.
• Integrate systems with external services.

Skills

C#

.NET Framework/Core

ASP.NET Core

Angular

WebAPI

Entity Framework

T-SQL

Git

Agile methodology

CI/CD

Tools

Docker

Kubernetes

TeamCity

Job description

About the role

We are looking for a Regular .NET Developer to join a team responsible for developing and maintaining core card payment systems - from transaction authorization and settlement to integrations with external payment services.

The systems process hundreds of thousands of transactions daily, so performance, availability and security are key priorities.

Work model: Remote-first with scheduled on-site team meetings (2 days per month in Warsaw).

Responsibilities

• Develop and maintain .NET applications in card payment domain
• Design and implement new functionalities according to business and regulatory requirements
• Integrate systems with external services (REST, SOAP, messaging queues)
• Optimize performance, availability and security of applications
• Cooperate with Analysts, Architects and QA in Agile/Scrum teams
• Participate in SIT/UAT testing, code reviews and preparation of technical documentation

Required skills

• Commercial experience with C# and .NET (Framework / Core)
• Experience with ASP.NET Core, Angular and WebAPI
• Knowledge of Entity Framework, LINQ, Dapper
• Experience with SQL Server (T-SQL) and query optimization
• Knowledge of SOLID principles and design patterns
• Experience writing unit tests (xUnit / NUnit)
• Experience with system integrations (REST, SOAP, JSON, XML)
• Experience working in Agile environment
• Knowledge of Git, CI/CD and TeamCity

Language requirements

• Polish: native or C2 level (required)
• English: professional level enabling work with technical documentation

Nice to have

• Experience in card payments / payment processing domain
• Knowledge of Docker / Kubernetes
• Experience working on high-availability or complex distributed systems

100 zł - 110 zł an hour

Margo Offers

• B2B cooperation
• Remote working model
• Benefits such as medical care and sports card
• Co‑financing trainings, certification exams and post‑graduate studies
• Ability to work in an international consulting company on ambitious projects
• Possibility to get involved in outside-project activities with additional remuneration
• Excellent working atmosphere, integration events