NET Software Engineer

Were looking for a Senior Software Engineer to design, build, and evolve our enterprise data APIs. This role will be actively involved in API architecture and delivery, contribute to a new API catalog and self-service discovery portal, and help drive AI-assisted improvements to how we design, build, and ship APIs.

Were looking for someone who combines strong hands-on engineering with the judgment to architect scalable, secure, well-documented APIs - and whos comfortable coordinating across teams to get there.

Essential Functions:

• Design, build, and maintain APIs using .NET.
• Architect API and database solutions for scalability, reliability, and maintainability.
• Design, optimize and integrate databases - MongoDB, PostgreSQL, MySQL, and OpenSearch - with APIs for efficient data storage, search, and retrieval.
• Use Kafka for event-driven and streaming integration patterns.
• Author and maintain API specifications using OpenAPI, ensuring consistent, well-documented API design standards.
• Contribute to a formal API catalog and registry - a developer portal where teams can discover available API endpoints through natural-language search.
• Help drive AI-assisted improvements to API development and delivery (e.g., AI-assisted code generation, testing, or monitoring).
• Debug and troubleshoot production issues using Grafana and related observability tooling.
• Identify and remediate security vulnerabilities using SonarQube (SAST), DAST tooling, and OWASP Top 10 best practices.
• Participate in requirement analysis, estimation, and deliverable planning in coordination with cross-functional teams.

Bachelors degree with 5-7 years of professional software engineering experience, or Masters degree with 3-5 years of experience, with a focus on API development.

Required Knowledge and Experience

• Strong hands-on experience with .NET.
• Solid experience designing, optimizing, and integrating MongoDB, PostgreSQL, MySQL, and OpenSearch with APIs.
• Experience with Kafka for messaging/streaming.
• Experience designing and documenting APIs with OpenAPI.
• Experience debugging and monitoring production systems using Grafana.
• Experience identifying and fixing security vulnerabilities using SAST tools (e.g., SonarQube), DAST tools, and OWASP-aligned practices.
• Strong communication skills, with proven experience in cross-team coordination.
• Experience with requirement analysis, estimation, and deliverable planning.

Preferred Qualifications

• Experience with Druid or Oracle.
• Exposure to AI/LLM-assisted development workflows.
• Experience with API catalog/registry or developer portal tooling., API Documentation, Apache Kafka, Application Programming Interface (API), Artificial Intelligence (AI), Automation, Best Practices, Communication Skills, Computer Security, Cross-Functional, Data Recovery, Data Storage, Database Architecture, Database Optimization, Debugging Skills, Documentation, Engineering, Genetics, Identify Issues, Intellectual Property (IP), Machine Tool, Microsoft .NET, Military, MongoDB, MySQL, Oracle, PostgreSQL, Price Book, Product Costing, Production Control, Production Systems, Requirements Management, Software Design, Software Engineering, Team Lead/Manager, Writing Skills

For over 35 years, Fintech LLC has redefined how over 1.1 million B2B relationships buy and sell goods and services in the retail, hospitality, and alcohol industries. This integrated platform centralizes invoice data and payments, POS and delivery data, product and cost compliance, price book management, and industry market data using AI, seamless integration capabilities, and proprietary automation technology.