Senior .NET Developer, AI-assisted development (part-time cooperation)

About the project
An AI-powered SaaS platform for digital customer and employee onboarding, identity verification (KYC/AML), and secure document collection, serving clients across property, banking, insurance, and legal sectors. The platform is ISO27001-certified and GDPR/CCPA-compliant, and is actively expanding into new markets, which requires new integrations and growing backend capacity.

You’ll join as a backend engineer on the existing .NET backend, working closely with the current DevOps and frontend (Vue.js) team members.

Engagement

• Part-time, ~40 hours/month to start for nearly 2 months, may flex up to 50 hours in peak periods. After a couple of months – ~20 hours/month.
• Hours are irregular/demand-driven rather than fixed daily hours — requires flexibility and responsiveness.
• Availability overlapping with client’s business hours needed for 2–3 short syncs/week plus a weekly tech review.
• Initially scoped for a couple of months, with likely extension depending on client growth.

Responsibilities

• Develop and maintain backend functionality in .NET / C#.
• Work with PostgreSQL: schema design, query and performance optimization.
• Design and maintain REST APIs and third-party integrations (incl. integrations with external systems as the product expands into new markets).
• Investigate and resolve production issues; support incident response.
• Improve performance and scalability for high-volume operations — including background/async processing for bulk data operations (e.g. large-scale record deletion, which currently causes timeouts).
• Participate in deployment (staging → production) and coordinate with DevOps on release processes.
• Review existing code/architecture and flag technical risks as the platform scales.
• Collaborate with frontend (Vue.js) and DevOps team members during releases and planning syncs.

• Use AI-assisted development tools in day-to-day work to accelerate delivery while maintaining correctness, security, and maintainability.

Required experience and skills

• 5+ years of commercial experience with .NET / C#, solid backend delivery track record.
• Solid PostgreSQL and relational database experience.
• Hands-on REST API design and third-party integration experience.
• Experience working within and improving existing production systems (not greenfield).
• Ability to investigate and solve problems with reasonable independence.
• Ability to ramp up on an existing, moderately complex codebase with limited onboarding time.
• Strong English communication for coordination with a client team based in a European timezone.
• 1+ year of experience using AI-assisted development tools (e.g., Codex, Claude Code, GitHub Copilot, Cursor) to accelerate system design, development, debugging, and testing while maintaining high code quality.
• Ability to critically evaluate and harden AI-generated solutions, ensuring correctness, security, and maintainability in production systems.

Nice to have

• Experience with Google Cloud Platform (GCP).
• CI/CD and deployment process experience.
• Experience with systems handling large data volumes / bulk operations.
• Experience with property, real estate, or identity-verification platforms.