Senior Full Stack Engineer
About The Position
As a Senior Software Engineer on the Platform Development team, you will play a key role in expanding the data platform that supports all of CoStar Group’s largest brands including CoStar Suite, LoopNet, Homes.com and Apartments.com. You will deeply understand what drives the business for which you are building software. We firmly believe that what separates a good developer from a great one is a deep understanding of the business that they are supporting. CoStar is investing heavily in artificial intelligence to accelerate software delivery, improve platform observability, automate research and business workflows, enhance product experiences through intelligent agents and skills, and improve data quality across enterprise systems. Successful candidates will demonstrate a willingness to learn, adopt, and apply AI technologies responsibly to solve complex business and engineering challenges.
Requirements
- Bachelor’s Degree required from an accredited, not for profit, in person, university or college.
- A track record of commitment to prior employers.
- 3+ years of deep .NET development (C#) development experience such as web APIs, background services, and developing and publishing shared packages.
- 5+ years of experience with TypeScript and modern frontend and backend JS tooling (e.g. Node, Vite, React, etc.).
- Experience with Infrastructure as Code (IaC) tools such as Terraform.
- Working knowledge and experience with cloud-based platforms (AWS or Azure).
- Experience in architecting, designing, and building large-scale distributed, service-oriented systems and web applications in an agile environment.
- Familiarity with using large language models (LLMs), context engineering, or agent-based architectures.
- Experience working with monitoring, telemetry, observability, or automated diagnostics platforms.
- Strong understanding of data quality principles, data governance concepts, and data-centric application design.
Nice To Haves
- Strong communication skills (to both business and technical partners).
- Experience with React Router Framework and Effect.
- SQL and database development knowledge.
- Experience using observability and APM platforms like Datadog.
- Familiarity with services such as Kafka, DynamoDB, and SQS.
- Experience with deploying to Kubernetes, EKS, and ECS.
- Data modeling experience from conceptual, logical, and physical designs.
- Experience implementing MCP clients and servers, workflow automation platforms, or intelligent search solutions.
- Experience applying AI-assisted software development practices to improve engineering productivity and code quality.
Responsibilities
- Build big, distributed, API-driven systems for tens of thousands of users.
- Build and integrate AI skills, agents, tools, and intelligent workflows into internal systems and customer-facing applications across CoStar brands, improving platform intelligence and unlocking new product capabilities.
- Produce code that is robust, efficient, and maintainable; our primary tools are TypeScript, C#, .NET, SQL Server, AWS.
- Build and maintain customer-facing and internal web applications using React/TypeScript.
- Utilize AI models to enhance monitoring, replayability, observability, and diagnostic capabilities to improve system reliability, accelerate problem resolution, and reduce operational risk.
- Drive and lead software design, development standards, and code review practices.
- Collaborate with Product, Research, and Data teams to identify opportunities where AI-driven workflows and automation can create business value and improve decision-making.
Benefits
- Generous compensation and performance-based incentives.
- Internal training.
- Tuition reimbursement.
- Comprehensive healthcare coverage: Medical / Vision / Dental / Prescription Drug
- Life, legal, and supplementary insurance
- Virtual and in person mental health counseling services for individuals and family
- Commuter and parking benefits
- 401(K) retirement plan with matching contributions
- Employee stock purchase plan
- Paid time off
- On-site fitness center and/or reimbursed fitness center membership costs (location dependent)
- Access to CoStar Group’s Employee Resource Groups
- Complimentary gourmet coffee, tea, hot chocolate, fresh fruit, and other healthy snacks
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What This Job Offers
Job Type
Full-time
Career Level
Senior
