Senior Full-Stack Engineer: AI-Driven Platform & APIs

CoStar; Arlington (VA); Hybrid; USD 143,000 - 187,000; Full time

Benefits offered by this job

Healthcare coverage

401(k) retirement plan with matching

Employee stock purchase plan

Paid time off

Tuition reimbursement

Job summary

CoStar Group, a leading real estate data provider, is seeking a Senior Full Stack Engineer in Arlington, VA. The role focuses on expanding the data platform across CoStar Suite, LoopNet, Homes.com, and Apartments.com, with AI-driven features and robust cloud infrastructure.

You will work in a hybrid model (in office Mon-Thu, remote Fri) and contribute to scalable systems using TypeScript, C#, .NET, and AWS while shaping product capabilities with AI integrations.

Qualifications

• Bachelor’s degree from an accredited university.
• 3+ years of deep .NET (C#) development including web APIs and services.
• 5+ years of TypeScript with modern frontend and backend JS tooling (Node, Vite, React).
• Experience with Terraform and IaC practices.
• Cloud experience on AWS or Azure.
• Experience building large-scale distributed systems in agile environments.
• Familiarity with LLMs, context engineering, or agent-based architectures.

Responsibilities

• Build big, distributed, API-driven systems for tens of thousands of users.
• Integrate AI skills, agents, tools, and workflows across platforms and products.
• Produce robust, maintainable code using TypeScript, C#, .NET, SQL Server, AWS.
• Develop customer-facing and internal web apps with React/TypeScript.
• Use AI to improve monitoring, observability, and diagnostics; reduce risk.
• Lead software design, standards, and code reviews.
• Collaborate with Product, Research, and Data teams on AI-driven value.

Skills

TypeScript

C#

React

AWS

Terraform

Kubernetes

Datadog

LLMs familiarity

Observability

AI awareness

Education

Bachelor’s Degree

Tools

Terraform

Kubernetes

DynamoDB

SQS

Kafka

Datadog

Job description

CoStar Group, a leading real estate data provider, is seeking a Senior Full Stack Engineer in Arlington, VA. The role focuses on expanding the data platform across CoStar Suite, LoopNet, Homes.com, and Apartments.com, with AI-driven features and robust cloud infrastructure.

You will work in a hybrid model (in office Mon-Thu, remote Fri) and contribute to scalable systems using TypeScript, C#, .NET, and AWS while shaping product capabilities with AI integrations.