Senior Full Stack Developer - AI First

RethinkFirst company; New York (NY); On-site; USD 140,000 - 190,000; Full time

Benefits offered by this job

Health insurance

Dental insurance

Vision insurance

Flex Paid time off

Parental leave

Professional development assistance

401K

Job summary

RethinkFirst in New York, NY, is seeking a Senior Full-Stack .NET Developer to design, test, and deploy cloud-based applications. You will work with C#, .NET Core, SQL, and modern front-end tech while supporting microservices and infrastructure in Azure/AWS.

The ideal candidate has 5+ years of development experience, strong domain-driven and event-driven design knowledge, and a proven ability to write clean, scalable code. AI tooling like Cursor and GitHub Copilot are part of daily workflow.

Qualifications

• Bachelor's degree in Computer Science or equivalent.
• 5+ years of development experience.
• Proficient with C#, JavaScript, and TypeScript.
• 3+ years of experience with Azure or AWS cloud technologies.
• Experience developing and deploying IaC.
• Deep understanding of domain and event driven design.
• Knowledge of design principles, algorithms, and data structures.
• Proficient in Git and unit/integration testing.
• Daily use of AI development tools like Cursor, Claude, or GitHub Copilot.

Responsibilities

• Design and build applications, micro-services, and infrastructure for the platform.
• Ensure performance, quality, and responsiveness of applications.
• Collaborate with a team to define, design, and ship new features.
• Identify and fix bottlenecks and bugs.
• Maintain code quality, organization, and automation.
• Leverage AI tools daily to improve development workflow.

Skills

C#

JavaScript

TypeScript

Domain-driven design

Event-driven design

Unit tests

Git

Code review

Education

Bachelor's degree in Computer Science

Tools

Azure

AWS

Azure DevOps

Docker

Kubernetes

Terraform

GitHub Copilot

Job description

About RethinkFirst

ReThinkFirst is on a mission to inspire hope and power potential. Founded in 2008 and headquartered in NYC, RethinkFirst is a pioneer and market leader in behavioral and mental health technology.

Developed by nationally recognized experts in the field, Rethink’s award-winning online solutions feature comprehensive video-based training and education programs and a sophisticated behavior intervention planning tool for individuals and caregivers. Rethink’s offerings include individualized assessments, online skills-based activities, access to remote clinician-led consultations, and more.

The Rethink First platform is used by Fortune 500 companies, school districts, government agencies, public and private behavioral health providers, and families caring for individuals with developmental disabilities worldwide.

We are hiring for a Full-Stack Senior .NET Developer to help deliver cloud-based applications and infrastructure to our growing customer base. The candidate will develop, design, test and deploy websites as well as support and maintain existing functionality. They should be experienced and productive with Microsoft development technologies, have a solid understanding of design patterns, object orientated programming and SOLID best practices. We take an AI-first approach to engineering: AI coding tools are the default way we work, and we expect developers to reach for them first on everything from scaffolding and refactoring to debugging, testing, and code review. Experience in health IT or insurance industry a plus.

Technology stack

• C#, .NET & .NET Core, SQL, Redis, Web API, JavaScript, HTML/CSS, Angular, TypeScript, Microservices, XUnit, Azure, CI/CD, Git, NGRX, OAuth.
• AI Tooling: Cursor, Claude, GitHub Copilot.
• Preferred Skills: Azure DevOps, Docker, Kubernetes, Terraform.

Responsibilities

• Design and build applications, micro-services, and infrastructure for the Rethink First platform.
• Ensure the performance, quality, and responsiveness of applications.
• Collaborate with a team to define, design, and ship new features.
• Identify and correct bottlenecks and fix bugs.
• Help maintain code quality, organization, and automation.
• Use AI development tools such as Cursor, Claude, and GitHub Copilot as your day-to-day toolset, and help the team get more out of them without compromising code quality or security.
• Analyze and optimize applications for efficiency and performance.
• Promote robust and maintainable code, clear documentation, and deliver high-quality work on a tight schedule.

Requirements

• Bachelor's degree in Computer Science
• 5+ years’ development experience
• Proficient with C#, JavaScript, and TypeScript
• 3+ years’ experience with Azure or AWS cloud technologies.
• Experience developing and deploying IaC.
• Deep understanding of domain and event driven design.
• Knowledge of modern architecture patterns.
• Understanding of design principles, algorithms, and data structures.
• Proficient understanding of code versioning tools such as Git.
• Experience writing and automating unit testsand integration tests.
• Daily hands-on use of AI development tools such as Cursor, Claude, or GitHub Copilot as a primary part of your workflow.
• Demonstrated fluency in AI-assisted workflows — prompting effectively, reviewing and correcting AI-generated code, and knowing when not to rely on it.

This Job Is Ideal for Someone Who Is

• Dependable -- more reliable than spontaneous.
• People-oriented -- enjoys interacting with people and working on group projects.
• Adaptable/flexible -- enjoys doing work that requires frequent shifts in direction.
• Detail-oriented -- would rather focus on the details of work than the bigger picture.
• Achievement-oriented -- enjoys taking on challenges, even if they might fail.
• Autonomous/Independent -- enjoys working with little direction.
• Innovative -- prefers working in unconventional ways or on tasks that require creativity.
• High stress tolerance -- thrives in a high-pressure environment.

Job Type

• Full-time

Work location

• Remote opportunities are available to candidates who reside in the following states: AL, AZ, CT, FL, GA, HI,IA,IL, IN, KY, LA, MD, MA, MI, MN, MO,MT,NC, NE, NH, NJ, NV, OH, OR, PA, RI, TN, TX, VA, WA, WI, WY

Benefits

• Health insurance
• Dental insurance
• Vision insurance
• Flex Paid time off
• Parental leave
• Professional development assistance
• 401K

Our commitment to an inclusive workplace

RethinkFirst is an equal opportunity employer and is committed to providing a workplace free from harassment and discrimination. We celebrate the unique differences of our employees because that is what drives curiosity, innovation, and the success of our business. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, age, pregnancy, genetic information, disability, status as a protected veteran, or any other protected category under applicable federal, state, and local laws. Accommodations are available for applicants with disabilities.