Senior Full-Stack Engineer - AI-Driven Platform (Hybrid)

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

Benefits offered by this job

Health insurance

401(k) matching

Tuition reimbursement

Job summary

CoStar Group is hiring a Senior Full Stack Engineer to expand the data platform that powers CoStar Suite, LoopNet, Homes.com and Apartments.com. The role focuses on building scalable, API-driven systems with TypeScript, C#, .NET, SQL Server, and AWS, while integrating AI-driven workflows across brands.

You will collaborate with Product, Research, and Data teams and contribute to observability, monitoring, and diagnostic capabilities to improve reliability.

Qualifications

• 3+ years of deep .NET development (C#) with web APIs and background services.
• 5+ years of TypeScript and modern frontend/backend JS tooling.
• Experience with Terraform and cloud platforms (AWS or Azure).
• Experience architecting large-scale distributed services in an Agile environment.
• 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 into internal systems and customer apps.
• Produce robust, efficient, maintainable code using TypeScript, C#, .NET, SQL Server, AWS.
• Build and maintain customer-facing and internal web apps using React/TypeScript.
• Lead software design, development standards, and code reviews.

Skills

Strong communication skills

TypeScript experience

LLM / agent-based architectures

Agile software development

Education

Bachelor's degree in Computer Science or related

Tools

Terraform

AWS

Azure

React

Node.js

Kubernetes

EKS

SQS

DynamoDB

Datadog

Kafka

SQL Server

Job description

CoStar Group is hiring a Senior Full Stack Engineer to expand the data platform that powers CoStar Suite, LoopNet, Homes.com and Apartments.com. The role focuses on building scalable, API-driven systems with TypeScript, C#, .NET, SQL Server, and AWS, while integrating AI-driven workflows across brands.

You will collaborate with Product, Research, and Data teams and contribute to observability, monitoring, and diagnostic capabilities to improve reliability.