System Engineer (.NET)

TL;DR

System Engineer (.NET): Maintaining, stabilizing, and modernizing a large monolithic backend platform with an accent on legacy component migration, API design, and database optimization. Focus on refactoring codebases, implementing REST/GraphQL APIs, extracting services to cloud, and ensuring production stability under load.

Location: Cologne/Remote (hybrid or fully remote with flexible hours, varies by role and team; offices in Cologne and Chicago)

Company

Premium Merchant of Record (MoR) simplifying global software sales through payments, subscriptions, taxes, compliance platform, and expert services.

What you will do

• Maintain and enhance large monolithic C#/.NET backend platform without disrupting production stability.
• Migrate legacy .NET Framework components to modern .NET versions and extract into cloud-based services.
• Design, implement, and maintain REST and GraphQL APIs, including schema evolution and third-party integrations.
• Develop and optimize Oracle SQL queries, database interactions, and WPF Windows desktop application.
• Investigate production issues, perform root-cause analysis, and improve CI/CD pipelines for delivery workflows.
• Refactor codebases to boost maintainability, stability, and long-term sustainability.

Requirements

• Strong experience with C# and modern .NET development.
• Experience maintaining/evolving large legacy/monolithic systems and migrating .NET Framework to modern versions.
• REST and GraphQL API design/maintenance (schema, resolvers, performance).
• Strong SQL skills, preferably Oracle; WPF for Windows desktop apps.
• Git workflows, code review, CI/CD pipelines.

Nice to have

• AWS services (API Gateway, Lambda, IAM, EventBridge, SQS), Terraform/Terragrunt.
• System modernization strategies, observability (logging/monitoring), performance optimization.

Culture & Benefits

• Flexible hybrid/remote work with flexible hours (varies by role/team).
• Modern offices in Cologne and Chicago.
• Gym reimbursement, wellness challenges, health benefits, 401(k)/pension, volunteer time off, mentoring.
• Learning & development programs with personal L&D budget.
• Referral bonuses; diverse, equal opportunity employer.