{"id":1384575,"url":"https://alion.io/job/costargroup-principal-software-engineer","title":"Principal Software Engineer","company":{"id":6056,"name":"CoStar Group","domain":"costargroup.com","url":"https://alion.io/company/costargroup","size_band":"1001-5000","is_staffing_agency":false,"employer_type":"direct","is_intermediary":false,"listed_via":null,"ats_vendor":"Workday","truth_index":{"grade":"B","score":75,"open_postings":77,"ghost_share":0,"stale_share":0.987,"repost_share":0,"time_to_fill_p50_days":30,"computed_at":"2026-10-07T05:47:15Z"}},"role":"Backend","role_family":"Backend","seniority":"lead","employment_type":"full_time","work_mode":"hybrid","remote_scope":null,"remote_scope_basis":null,"remote_working_hours":null,"hiring_geo_confidence":"structured","locations":["Irvine, United States"],"countries":["US"],"hiring_countries":[],"hiring_countries_total":0,"salary":{"min":214000,"max":297000,"currency":"USD","period":"year","gross":null,"usd_annual":297000},"salary_estimate":null,"experience_years_min":10,"visa_sponsorship":true,"relocation_package":false,"has_equity":true,"technologies":[{"name":"Agile","optional":true},{"name":"Amazon CloudWatch","optional":true},{"name":"Amazon S3","optional":true},{"name":"API Gateway","optional":true},{"name":"AWS","optional":true},{"name":"AWS Lambda","optional":true},{"name":"Azure","optional":true},{"name":"Azure DevOps","optional":true},{"name":"C#","optional":true},{"name":"CI/CD","optional":true},{"name":"CloudFormation","optional":true},{"name":"DynamoDB","optional":true},{"name":"GCP","optional":true},{"name":"Git","optional":true},{"name":"GraphQL","optional":true},{"name":"JavaScript","optional":true},{"name":"Kibana","optional":true},{"name":"Python","optional":true},{"name":"Terraform","optional":true},{"name":"TypeScript","optional":true}],"status":"live","first_seen_at":"2026-09-22T00:00:00Z","employer_posted_date":"2026-09-22","last_verified_at":"2026-10-08T00:05:36Z","board_verified":true,"closed_at":null,"days_open":16,"trust":{"level":"ok","repost_count":null,"flags":[],"days_open":16},"description":"Principal Software EngineerJob Description\nOverview\nCoStar Group (NASDAQ: CSGP) is a leading global provider of commercial and residential real estate information, analytics, and online marketplaces. Included in the S&P 500 Index, CoStar Group is on a mission to digitize the world’s real estate, empowering all people to discover properties, insights and connections that improve their businesses and lives.\nWe have been living and breathing the world of real estate information and online marketplaces for over 35 years, giving us the perspective to create truly unique and valuable offerings to our customers. We’ve continually refined, transformed, and perfected our approach to our business, creating a language that has become standard in our industry, for our customers, and even our competitors. We continue that effort today and are always working to improve and drive innovation. This is how we deliver for our customers, our employees, and investors. By equipping the brightest minds with the best resources available, we provide an invaluable edge in real estate.\nOur CoStar development team is looking for an experienced Principal Software Engineer to own the architecture and design of our software systems, from full stack web products to high-volume, secure data pipelines. This role includes design of new greenfield systems, so being able to convert product requirements to system architecture is essential. It will also help guide the ongoing architectural evolution of our current solutions, meaning the ability to fully understand existing complex systems is required as well.\nIt is a highly collaborative role that comes with great influence on the technical solutions we are building and requires strong communication and cooperation across multiple teams and disciplines. This includes developers within the same team and Software Architects throughout the company. To be successful in this role you must be a problem-solving, collaborative person with deep technical skills, and the ability to work in a secure, performant, enterprise-scale environment.\nThis position will be located in Irvine) and is in office Monday through Thursday and work from home on Friday.\nResponsibilities:\nWork in partnership with Product and Technology leadership to deeply understand a project’s complex functional requirements and drive implementation of appropriate technical solutions.\nCollaborate with development teams to determine the right architectural direction based on project needs, level of effort, resourcing, timing, etc.\nUnderstand existing systems and ensure they are well documented, so that you become a go-to source of architectural information across multiple systems.\nAct as an architectural subject matter expert and source of good advice to technical leadership and developers.\nDrive and evangelize architectural principles and guidelines to ensure high quality, consistent results across teams.\nPartner with engineering managers to ensure that they are following established architectural best practices.\nCreate, organize, and maintain architectural diagrams and other system documentation.\nProvide architectural guidance and mentoring to other technical staff on topics such as microservices, micro-frontends, high-volume data streaming / event processing, etc.\nStay up to date with emerging technologies, evaluate and development practices and identify how they might improve existing or new systems we are building.\nDevelop a deep understanding of the CoStar business, and how the technical work we are doing aligns with that strategy.\nAdvocate for and design solutions that are well-instrumented, so that we are confident we are building stable, high-performance products.\nBe a go-to resource in the understanding and diagnosis of complex performance, scalability, and reliability issues.\nBe an advocate for security and ensure that we are architecting and building secure software products and platforms.\nBasic Qualifications:\nBachelor’s Degree required from an accredited, not-for-profit, in-person college/university\nA track record of commitment to prior employers\n10+ years of hands-on experience in designing highly complex enterprise-level web applications, including deep knowledge of microservices, serverless, data, and web applications.\nExperience designing and buildings secure systems and security minded development practices. Experience with financial data is a big plus.\nExtensive experience in software engineering with expert-level proficiency in at least one of these programming languages: C#, Java, Python, JavaScript/TypeScript. Exposure to languages and platforms across the full web application stack is a big plus (e.g., GraphQL).\nSignificant, hands-on experience designing and implementing solutions using Amazon Web Services (AWS) services including Lambda, DynamoDB, CloudWatch, CloudFormation, SNS/SQS, S3, API Gateway, etc.\nExperience with Test Driven Development methodologies.\nExperience modeling and implementing large-scale relational and NoSQL database systems.\nExperience designing/implementing event-oriented architectures and real-time data streaming solutions.\nStrong ability to communicate through architectural diagrams.\nPreferred Qualifications:\nArchitect-level certifications from AWS, Azure or GCP\nExperience with agile development methodologies.\nExperience with modern source control and CI/CD technologies including Git or Azure DevOps.\nExperience establishing software development best practices, including standards, code reviews, source control, builds, testing and operations.\nExperience with Infrastructure as Code in Terraform.\nExperience in observability logging/tracing with CloudWatch and/or Kibana.\nExperience building highly secure software, including tokenization, OpenID, etc.\nTeam or project leadership experience is a plus.\nWhat's in it for you?\nWhen you join CoStar Group, you’ll experience a collaborative and innovative culture working alongside the best and brightest to empower our people and customers to succeed.\nWe offer you generous compensation and performance-based incentives. CoStar Group also invests in your professional and academic growth with internal training and tuition reimbursement.\nOur benefits package includes (but is not limited to):\nComprehensive healthcare coverage: Medical / Vision / Dental / Prescription Drug\nLife, legal, and supplementary insurance\nVirtual and in person mental health counseling services for individuals and family\nCommuter and parking benefits\n401(K) retirement plan with matching contributions\nEmployee stock purchase plan\nPaid time off\nTuition reimbursement\nOn-site fitness center and/or reimbursed fitness center membership costs (location dependent)\nAccess to CoStar Group’s Employee Resource Groups\nComplimentary gourmet coffee, tea, hot chocolate, fresh fruit, and other healthy snack\nThe final salary or hourly rate offered for this role will fall within the range set forth below based on a variety of factors, including but not limited to, geographic location, skills, and competencies.\nBase Compensation: $214,000 - $297,000 (Hourly/Annually)\nWe welcome all qualified candidates who are currently eligible to work full-time in the United States to apply. However, please note that CoStar Group is not able to provide visa sponsorship for this position.\nCoStar Group is an Equal Employment Opportunity Employer; we maintain a drug-free workplace and perform pre-employment substance abuse testing","description_format":"text","description_chars":7451,"description_truncated":false,"requirements":{"experience_years_min":10,"management_years_min":null,"team_size_min":null,"manages_managers":false,"education":{"level":"bachelor","optional":false},"security_clearance":false,"languages":[]},"benefits":["Retirement plans"],"hiring_locations":[{"name":"United States","iso":"US","kind":"country"}],"hiring_excludes":[],"relocation_offered":false,"industries":["Professional Services","Real Estate","E-learning","Virtual Events"],"lifecycle":[{"event":"open","at":"2026-09-28T09:52:41Z"}],"visa":[],"liveness":{"score":55,"band":"ok","label":"Likely open","p_open":1,"p_active":0.61,"p_room":0.9,"age_days":15,"expected_fill_days":30,"reasons":["conf:4","stale_co","velocity","win:mid","comp:brand"],"computed_at":"2026-10-07T05:47:15Z"},"pay":{"stated_usd_annual":297000,"is_top_pay":true},"html_url":"https://alion.io/job/costargroup-principal-software-engineer","json_url":"https://alion.io/job/costargroup-principal-software-engineer.json","meta":{"generated_at":"2026-10-08T02:09:24Z","cache_seconds":300,"methodology":"https://alion.io/methodology","terms":"https://alion.io/terms","contact":"https://alion.io/contact","api":"https://alion.io/developers","about":"Alion is a live layer of people, companies and AI agents: who they are, whether they are real and active right now, what they do and how to work with them, readable by people and by agents and paid per call.","catalog":"https://alion.io/catalog.json","usage":{"tier":"crawler","counted_by":"address","units_charged":1,"used_today":3788,"day_limit":5000,"remaining_today":1212,"minute_limit":60,"resets_at":"2026-10-09T00:00:00Z"}},"offers":[{"id":"company.slices","title":"One company in depth, by slice","status":"live","price":{"credits":0.02,"usd":0.002,"plus_per_slice":{"credits":0.05,"usd":0.005}},"unit":"per company, plus each slice with data","note":"the employer in depth","call":{"mcp_tool":"get_company","arguments":{"id":6056},"rest":"https://alion.io/mcp/rest/get_company?id=6056"},"human":"https://alion.io/catalog?offer=company.slices&for=job%2Fcostargroup-principal-software-engineer"},{"id":"market.stats","title":"A market slice: pay, demand and time to fill","status":"live","price":{"credits":1,"usd":0.1},"unit":"per slice","note":"pay, demand and time to fill for this role and place","call":{"mcp_tool":"market_stats"},"human":"https://alion.io/catalog?offer=market.stats&for=job%2Fcostargroup-principal-software-engineer"},{"id":"job.search","title":"Open jobs by role, technology, place, pay and visa","status":"live","price":{"credits":0.02,"usd":0.002},"unit":"per posting in a list","note":"similar open postings","call":{"mcp_tool":"search_jobs"},"human":"https://alion.io/catalog?offer=job.search&for=job%2Fcostargroup-principal-software-engineer"},{"id":"company.verify","title":"Is this company real and active right now","status":"pilot","price":null,"unit":"per company","request":{"url":"https://alion.io/catalog/request","method":"POST","body":"{\"offer\": \"company.verify\", \"for\": \"job/costargroup-principal-software-engineer\", \"note\": \"what you need it for\"}"},"human":"https://alion.io/catalog?offer=company.verify&for=job%2Fcostargroup-principal-software-engineer"}]}