{"id":711874,"url":"https://alion.io/job/facilityos-senior-software-engineer","title":"Senior Software Engineer","company":{"id":673462,"name":"FacilityOS","domain":"facilityos.com","url":"https://alion.io/company/facilityos","size_band":"51-200","is_staffing_agency":false,"is_intermediary":false,"ats_vendor":"Ashby","truth_index":null},"role":"Backend","role_family":"Backend","seniority":"senior","employment_type":"full_time","work_mode":"hybrid","remote_scope":null,"hiring_geo_confidence":"structured","locations":["Annapolis, United States"],"countries":["US"],"hiring_countries":[],"hiring_countries_total":0,"salary":null,"salary_estimate":{"min_usd":93000,"max_usd":173000,"period":"year","method":"role_seniority_country_remote_cell","sample_n":1999},"experience_years_min":8,"visa_sponsorship":false,"relocation_package":false,"has_equity":false,"technologies":[{"name":".NET","optional":false},{"name":"C#","optional":false},{"name":"Clean Architecture","optional":false},{"name":"MS SQL","optional":false}],"status":"live","first_seen_at":"2026-07-13T02:41:45Z","employer_posted_date":"2026-07-13","last_verified_at":"2026-09-23T11:53:19Z","board_verified":true,"closed_at":null,"days_open":72,"trust":{"level":"ok","repost_count":null,"flags":[],"days_open":72},"description":"About FacilityOS\nFacilityOS is a fast-growing company redefining how facilities operate-bringing safety, security, and daily operations into one unified platform used by organizations around the world.\nAs we continue to scale globally, we’re building a team of driven, curious people who want to make an impact. You’ll be part of a dynamic, collaborative culture where individuals are trusted to take ownership, solve meaningful problems, and grow in their careers. Our team comes together in-office twice a week to connect, collaborate, and build momentum.\nIf you’re looking to do your best work alongside a great team in a high-growth environment, FacilityOS is the place to build your career.\nAbout the Role:\nWe are looking for a highly capable Sr. Back-End Engineer who can ramp up quickly, collaborate effectively with the existing team, and begin contributing meaningful delivery outcomes within the first few weeks. This role is well suited for someone who is comfortable navigating legacy systems, applying strong architectural principles, and making thoughtful technical decisions that improve delivery throughput without compromising quality.\nThe ideal candidate brings strong backend engineering experience, sound judgment, and the ability to work independently while staying closely aligned with team standards and architectural direction.\nThis role is a hybrid position where you’ll be required to come into our office three (3) times a week.\nDuties and Responsibilities\nDesign, develop, review, and maintain backend web applications and services across the FacilityOS platform.\n\nQuickly develop a working understanding of existing platform architecture, legacy components, integration points, and modernization opportunities.\n\nCollaborate with the engineering team to make sound technical decisions that align with established architectural principles and delivery goals.\n\nContribute to legacy modernization efforts using incremental, low-risk approaches such as the Strangler Fig pattern where appropriate.\n\nMaintain high code-quality standards through code reviews, unit testing, static code analysis, and the adoption or improvement of engineering tools and standards.\n\nParticipate actively in peer code reviews, providing constructive feedback and helping promote maintainable, testable, and scalable solutions.\n\nTroubleshoot and resolve application issues across environments, including staging and production, with a focus on root-cause analysis and sustainable fixes.\n\nWork directly with engineering leads, product stakeholders, and project managers to support business operations and project delivery.\n\nResearch, evaluate, and recommend innovative application, automation, and architectural improvements that would benefit the FacilityOS platform.\n\nSkills and Qualifications\nMinimum of 8 years of proven experience in backend .NET Framework / .NET Core web application development using C#.\n\nProven ability to quickly understand complex legacy systems, identify key integration points, and contribute effectively with limited ramp-up time.\n\nProven experience applying the Strangler Fig pattern or similar modernization approaches to gradually replace or refactor legacy systems.\n\nStrong experience using object-oriented programming, design patterns, and clean architecture principles to build maintainable, testable software.\n\nProven experience writing unit tests and applying quality-focused development practices.\n\nProven experience designing and building RESTful services.\n\nExperience designing and building cloud-native SaaS and PaaS applications.\n\nSolid knowledge of Microsoft SQL Server and T-SQL.\n\nAbility to make sound technical decisions in collaboration with existing engineering teams.\n\nProactive, curious, and investigative mindset with strong attention to quality and detail.\n\nPassion for technology, continuous improvement, and modern engineering practices.\n\nAbility to self-manage priorities and deliver outcomes with minimal supervision.\n\nStrong team-player attitude with the ability to collaborate across engineering, architecture, and product stakeholders.\n\nWhy work at FacilityOS?\nWe work hard and play hard and we do both with passion and respect for one another. Our company promotes a fast-paced, fun, friendly, and highly collaborative work environment that provides:\nComprehensive health coverage\nA Hybrid work environment\nOpportunity for advancement and growth\nCatered Events, Snacks, Drinks - You won’t go Hungry!\nBirthday and Life Celebrations\nTwo annual parties in a year\nFacilityOS Commitment\nWe believe that a diverse team is the key to innovation and growth. We are an equal opportunity employer that value diversity at our company and encourage all candidates to apply. We do not discriminate based on race, religion, color, national origin, gender, sexual orientation, age, marital status, veteran status, or disability status.\nFacilityOS will accommodate individuals with disabilities through each stage of the recruitment and selection process. Please advise us of any needs when your interview is booked, and we will do our best to meet your needs.\nPlease note that all candidates must be legally eligible to work in the location in which you applied.\nBackground and Reference Checks\nAny offer of employment may be conditional upon full background checks including a criminal record check, a credit check and employment and educational verifications. A reference check will also be conducted.\nWe may use artificial intelligence (AI) tools to support parts of the hiring process such as reviewing applications. These tools assist the recruitment team but do not replace human judgment. All advancement and hiring decisions are ultimately made by humans. If you would like more information about how your data is processed, please contact us or click here.\nFacilityOS thanks all candidates for their interest, however only those selected to continue in the process will be contacted.","description_format":"text","description_chars":5939,"description_truncated":false,"requirements":{"experience_years_min":8,"management_years_min":null,"team_size_min":null,"manages_managers":false,"education":null,"security_clearance":false,"languages":[]},"benefits":["Hybrid work"],"hiring_locations":[{"name":"United States","iso":"US","kind":"country"}],"hiring_excludes":[],"relocation_offered":false,"industries":["Real Estate","Property Management","Facilities Management"],"lifecycle":[{"event":"open","at":"2026-09-11T04:57:11Z"}],"liveness":{"score":17,"band":"cold","label":"Long shot","p_open":1,"p_active":0.482,"p_room":0.36,"age_days":72,"expected_fill_days":43,"reasons":["conf:1","win:tail","crowd:"],"computed_at":"2026-09-23T05:45:00Z"},"pay":null,"html_url":"https://alion.io/job/facilityos-senior-software-engineer","json_url":"https://alion.io/job/facilityos-senior-software-engineer.json","meta":{"generated_at":"2026-09-23T12:21:35Z","cache_seconds":300,"methodology":"https://alion.io/methodology","terms":"https://alion.io/terms","contact":"https://alion.io/contact","api":"https://alion.io/developers"}}