Backend .NET Developer

Solid Company; Wrocław; Hybrid; PLN 120,000 - 180,000; Full time

Benefits offered by this job

Attractive salary

Fully remote work allowed

Professional development opportunities

Influence project direction

Job summary

Solid Company is seeking a skilled C#/.NET developer to design and implement integrations with external systems (SOAP/XML and REST/JSON). You will map data models, handle partner errors, and build robust async exchanges using message queues.

Join our remote-first team in Poland, contribute to OpenAPI driven client implementations, develop mocks, and support BPMN-based business logic in C#. Excellent English for technical docs is expected.

Qualifications

• 3–4 years of experience in a similar role.
• Experience with AI tools in development.
• Strong knowledge of C# and .NET (ASP.NET Core, .NET 8+).
• Experience with SOAP/XML integrations, REST/OpenAI integrations.
• Asynchronous architecture with message queues (RabbitMQ or equivalent), request-callback pattern, idempotency, persistence of exchange state.
• Good knowledge of databases.
• Domain model mapping.
• Docker and CI/CD.
• Git in gitflow model.
• English proficiency for reading technical documentation.
• Communicative and collaborative with client-side personnel.
• Ability to work independently.

Responsibilities

• Design and implement integrations with external systems (SOAP/XML and REST/JSON services), including data model mapping and partner error handling.
• Maintain and develop asynchronous data exchange mechanisms (message queues, callbacks, statuses, request idempotency).
• Generate and update API clients based on OpenAPI contracts provided by the client; respond to contract version changes.
• Build and maintain mocks of external systems for test environments.
• Implement business process logic in a BPMN engine (handlers in C#, process variables, signals) and decision rule models.
• Configure environments (installation parameters, Docker, CI/CD pipeline), participate in releases and hotfixes.
• Analyze defects from business tests and production based on logs; quick fixes with client analysts/testers.
• Document solutions and transfer knowledge within the team.

Skills

C#

.NET

Asynchronous messaging

REST/JSON

SOAP/XML

OpenAI integration

RabbitMQ

CI/CD

Git (gitflow)

English docs

Independent work

Collaboration

Tools

ASP.NET Core

.NET 8

Docker

OpenAPI

Job description

Requirements:

• Minimum 3-4 years of experience in a similar position
• Experience working with AI tools in development
• Very good knowledge of C# and .NET (ASP.NET Core, .NET 8 or newer)
• Practical experience with SOAP / XML integrations, REST/OpenAI integrations
• Asynchronous architecture - message queues (RabbitMQ or equivalent), request-callback pattern, idempotency, persistence of exchange state
• Good knowledge of databases
• Mapping of domain models
• Docker and CI/CD
• Git in gitflow model
• English language proficiency for reading technical documentation
• Communicative, open to collaboration with client-side personnel
• Ability to work independently

Additional advantages:

• Experience in the financial/banking industry or in projects for these industries

Kogo poszukujemy?

Responsibilities:

• Designing and implementing integrations with external systems (SOAP/XML and REST/JSON services), including data model mapping and partner error handling.
• Maintaining and developing an asynchronous data exchange mechanism (message queues, callbacks, statuses, request idempotency).
• Generating and updating API clients based on OpenAPI contracts provided by the client; responding to contract version changes.
• Building and maintaining mocks of external systems for test environments.
• Implementing business process logic in a BPMN engine (handlers in C#, process variables, signals) and decision rule models.
• Configuring environments (installation parameters, Docker, CI/CD pipeline), participating in preparing releases and hotfixes.
• Analyzing defects from business tests and production based on logs, quick fixes, collaborating with client analysts and testers.
• Documenting solutions and transferring knowledge within the team.

We offer:

• Attractive salary
• Possibility of fully remote work
• Real opportunity for professional development
• Possibility to genuinely influence the shape of projects