C#/.NET Engineer – ERP & QuickBooks Integration

Location: Ukraine, Europe — 100% Remote
Employment Type: Full-Time
Salary: $2,000–$2,500 USD/month
Required Working Hours: U.S. Eastern Time (ET)

About the Role

We are looking for an experienced C#/.NET Engineer based in Ukraine to join our development team and work primarily on ERP development and QuickBooks integrations.

This is a remote position, but candidates must be available to work U.S. Eastern Time business hours. This requirement is important because the engineer will collaborate directly with our U.S.-based engineering team, customers, and business stakeholders.

You will build and maintain backend services, APIs, synchronization processes, and integrations connecting our ERP platform with QuickBooks and other business systems.

Responsibilities

• Develop and maintain backend applications using C# and .NET / .NET Core.
• Build and maintain ERP integrations with QuickBooks.
• Develop integrations with QuickBooks Online (QBO) APIs.
• Work with customers, vendors, invoices, payments, bills, expenses, purchase orders, accounts, payroll-related data, and inventory.
• Design reliable two-way data synchronization between ERP and QuickBooks.
• Build REST APIs, webhooks, background services, and scheduled synchronization jobs.
• Implement OAuth 2.0 and other authentication mechanisms.
• Handle data mapping and transformation between ERP and QuickBooks.
• Troubleshoot synchronization failures, duplicate records, API errors, and data inconsistencies.
• Implement retry mechanisms, logging, monitoring, and error handling.
• Work extensively with SQL Server and relational data.
• Investigate and resolve production integration issues.
• Participate in code reviews and architecture discussions.
• Collaborate directly with U.S.-based developers, product managers, customers, and stakeholders.
• Participate in meetings and technical discussions during U.S. Eastern Time working hours.

Required Technical Skills

• 3+ years of professional C#/.NET development experience
• Strong C# programming skills
• .NET 6/7/8 or later
• ASP.NET Core / Web API
• REST API development and third-party integrations
• SQL Server
• Entity Framework / Entity Framework Core
• OAuth 2.0
• JSON and API data transformation
• Background workers and scheduled jobs
• Asynchronous programming (async / await)
• Git
• Strong debugging and troubleshooting skills

ERP & QuickBooks Experience

Experience in one or more of the following is strongly preferred:

• QuickBooks Online API
• QuickBooks Desktop integrations
• QuickBooks Web Connector
• ERP development
• Accounting system integrations
• Customer/vendor synchronization
• Invoice and payment synchronization
• Payroll integrations
• Inventory and purchasing workflows
• CRM-to-accounting integrations
• Financial data synchronization

Previous QuickBooks integration experience is highly preferred.

Nice to Have

• Microsoft Azure
• Azure Functions
• Azure App Service
• Azure SQL
• Azure Service Bus
• Docker
• CI/CD
• GitHub Actions or Azure DevOps
• Microservices
• Message queues
• Redis
• Vue.js, Angular, or React
• Multi-tenant SaaS experience
• Experience modernizing legacy .NET applications

Working Hours — Important

This position requires working according to the U.S. Eastern Time (ET) schedule.

Candidates must be comfortable working U.S. business hours from Ukraine and should be consistently available during the agreed Eastern Time schedule for:

• Daily development work
• Team meetings
• Customer meetings
• Technical discussions
• Production support
• Collaboration with U.S.-based team members