Senior Software Engineer (Back End)

Mpathic; Northern (KY); On-site; USD 120,000 - 180,000; Full time

Job summary

mpathic seeks a Senior Software Engineer (Back End) to design, build, and scale the systems powering our platform and AI safety work. You’ll own backend services with .NET (C#) and AWS, delivering reliable APIs and cloud-native data infrastructure.

Collaborate with product, AI, and frontend teams, make thoughtful architectural choices, and mentor others as we move fast while maintaining quality and security at scale.

Qualifications

• 5+ years of software engineering experience with backend focus on .NET (C#).
• Hands-on AWS experience with cloud-native applications.
• Strong SQL and NoSQL database experience and data modeling.
• Experience designing scalable backend services and APIs.
• Familiarity with React and frontend ecosystem.

Responsibilities

• Design, build, test, and maintain backend systems in .NET (C#) and related languages.
• Design, deploy, and manage scalable AWS applications (ECS Fargate, DynamoDB, S3).
• Develop reliable APIs and services for the platform and AI workflows.
• Collaborate with frontend and cross-functional teams; mentor others.
• Ensure code quality and contribute to engineering standards.

Skills

.NET (C#)

AWS

SQL/NoSQL

System design

React

Technical ownership

Frontend collaboration

Tools

ECS Fargate

DynamoDB

S3

Job description

About mpathic

mpathic is building the future of trustworthy AI. Grounded in behavioral science and human-centered design, we provide the infrastructure for building AI systems that are safe, aligned, and emotionally intelligent.

Building on our work in areas like RL gyms, red teaming, benchmarking, and human data, we are creating the foundation for training, probing, and measuring advanced AI systems reliably, auditably, and at scale.

Position Overview

mpathic is seeking a Senior Software Engineer (Back End) to help design, build, and scale the systems that power our platform and AI safety work.

This role will focus primarily on backend engineering using .NET (C#) and AWS, with responsibility for building reliable APIs, services, data infrastructure, and cloud-native applications. You’ll work closely with engineers and cross-functional partners to solve complex technical problems, improve the scalability and performance of our systems, and support the integration of AI models into our products and workflows.

We’re looking for an experienced engineer who is comfortable owning problems end-to-end, making thoughtful architectural decisions, and operating in a fast-moving environment where the problems we’re solving are still evolving.

About You

• Proven Experience: 5+ years of software engineering experience, with a strong focus on backend development using .NET (C#).
• AWS Proficiency: Hands-on experience with AWS services, architecture, and best practices for building and operating cloud-native applications.
• Database Expertise: Strong experience with SQL and NoSQL databases, including schema design, data modeling, query optimization, and performance.
• System Design: Experience designing scalable, reliable backend services, APIs, and distributed systems.
• Frontend Familiarity: Working knowledge of React and its ecosystem, with the ability to collaborate effectively across the stack.
• Technical Ownership: Comfortable taking ambiguous technical problems from initial requirements through design, implementation, testing, and deployment.
• Collaborative Mindset: Strong communicator who enjoys working across engineering, product, and other technical teams.
• Continuous Learning: Curious about emerging technologies and motivated to evaluate new tools and approaches pragmatically.

Core Responsibilities

• Backend Development: Design, build, test, and maintain robust backend systems using .NET (C#) and other languages as appropriate.
• Cloud Infrastructure: Design, deploy, and manage scalable applications in AWS, leveraging services such as ECS Fargate, DynamoDB, S3, and other cloud-native technologies.
• API & Service Development: Build reliable APIs and services that support mpathic’s platform, products, and AI workflows.
• Database Management: Work with both SQL databases, including PostgreSQL, and NoSQL databases, including DynamoDB, to support diverse application and data needs.
• System Design & Scalability: Make thoughtful architectural decisions around reliability, scalability, performance, security, and maintainability.
• AI Integration: Support the integration of AI models and AI-powered capabilities into production systems and workflows.
• Frontend Collaboration: Partner closely with frontend engineers and occasionally contribute to React-based applications when needed.
• Code Quality: Write clean, maintainable, well-tested, and well-documented code while contributing to engineering standards and best practices.
• Mentorship: Provide technical guidance to other engineers and actively participate in code reviews, architecture discussions, and knowledge sharing.
• Problem-Solving: Tackle complex engineering challenges spanning performance optimization, system design, troubleshooting, integrations, and evolving product requirements.
• Research & Experimentation: Stay current on emerging tools and techniques for cloud infrastructure, services, APIs, and AI applications. Conduct focused proofs of concept with clear technical and business outcomes.
• Cross-Functional Collaboration: Work closely with engineering, product, AI, and other teams to translate business and customer needs into scalable technical solutions.

What Success Looks Like

You’ll help mpathic build a backend foundation that can scale alongside our products and customers. You’ll take meaningful ownership of technical decisions, improve the reliability and maintainability of our systems, and help the broader engineering team move quickly without sacrificing quality.

You’ll also have the opportunity to work on technically challenging problems at the intersection of software infrastructure, AI, and human-centered AI safety.