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# Software Engineer III

- **Company:** Zinnia, Inc.
- **Location:** United States
- **Experience:** Expert
- **Contract:** Permanent contract
- **Skills:** ASP.NET, .NET Framework, Application Programming Interfaces (APIs), Agile Methodology, Artificial Intelligence, Amazon Web Services, Amazon Elastic Compute Cloud, Amazon S3, Software Applications, Application Performance Management, Automation of Tests, C Sharp (Programming Language), Code Review, Continuous Integration, Data Integration, Database Design, Database Queries, Software Design Patterns, Microsoft SQL Server, Model View Controller (MVC), OAuth, Object-Oriented Software Development, Performance Tuning, Scrum Methodology, Systems Development Life Cycle, Redis, Swagger, Simple Object Access Protocol (SOAP), Software Engineering, SQL Stored Procedures, SQL Server Reporting Services, Systems Integration, Extensible Markup Language (XML), Openapi, Enterprise Software Applications, .NET Core, ReactJS, Large Language Models, Prompt Engineering, Software Security, Reliability of Systems, Generative AI, Amazon Relational Database Service, AngularJS, Solid Principles, Front End Software Development, Functional Programming, Cloudwatch, Api Gateway, Restful APIs, Software Version Control, Api Management, Web Api
- **Published:** November 11, 2026
- **Apply:** https://startup.jobs/software-engineer-iii-zinnia-10741012

## About the Role

* 5+ years of professional, hands-on software development experience with C# and Microsoft .NET.
 * Strong command of C#/.NET and .NET Core, including MVC, Web API, and object-oriented development.
 * Demonstrated experience personally designing, building, testing, and maintaining RESTful APIs.
 * Strong SQL Server development experience, including complex queries, stored procedures, database design, and performance tuning.
 * Working knowledge of Kong (API gateway) and Redis in API and caching architectures.
 * Experience developing, deploying, or supporting cloud-hosted applications, preferably on AWS services such as EC2, S3, Lambda, RDS, and CloudWatch.
 * Familiarity with design patterns, SOLID principles, source control, automated testing, and CI/CD.
 * Experience contributing to the full SDLC within Agile/Scrum teams.
 * Exposure to integrating Generative AI or LLMs into software applications, such as through API integrations, prompt engineering, or AI-powered workflows.
 * Strong problem-solving and communication skills, with an interest in collaborating across global teams.
 * A demonstrated interest in continuing as a hands-on software developer.

BONUS POINTS:

 * Experience deploying and supporting LLM-powered functionality in production applications.
 * Familiarity with OAuth2, OpenAPI/Swagger, and API security practices.
 * Frontend experience with React or Angular.
 * Experience with enterprise SaaS platforms or insurance technology.
 * Familiarity with SOAP/XML integrations or SSRS.
 * Experience supporting regulated, high-volume enterprise applications.

## Description

Zinnia is looking for a hands-on Software Engineer III to help build, enhance, and support our Life & Annuity Exchange platforms.

We're looking for a strong C#/.NET developer who enjoys solving complex technical problems, designing reliable APIs, and building scalable enterprise applications. You'll contribute throughout the software development lifecycle, from technical design and development to testing, deployment, and production support.

You'll also have the opportunity to work with modern Generative AI capabilities, integrating LLM-powered functionality into enterprise applications and improving existing business workflows.

This is an individual-contributor engineering role for someone who wants to remain close to the code while collaborating with a global engineering team and contributing to technical decisions.

WHAT YOU'LL DO:

 * Design, develop, test, and maintain enterprise applications using C#, .NET, and ASP.NET Core.
 * Build and enhance secure RESTful APIs supporting Zinnia's Life & Annuity Exchange platforms.
 * Develop and optimize SQL Server database queries, stored procedures, and data integrations.
 * Integrate Generative AI and LLM capabilities into application features and business workflows.
 * Develop, deploy, and support cloud-hosted applications, primarily within AWS environments.
 * Troubleshoot production issues, improve application performance, and contribute to system reliability.
 * Partner with engineering, product, and business stakeholders to translate requirements into working software.
 * Participate in Agile development, code reviews, automated testing, and continuous improvement.
 * Share technical knowledge and mentor other engineers while maintaining hands-on development responsibilities.