{"id":2291832,"url":"https://alion.io/job/keyes-senior-full-stack-developer-net-corereact-90-remote-poland","title":"Senior Full Stack Developer (.NET Core/React) - 90 % Remote (Poland)","company":{"id":54374,"name":"Keyes","domain":"keyes.eu","url":"https://alion.io/company/keyes","size_band":"201-500","is_staffing_agency":false,"employer_type":"direct","is_intermediary":false,"listed_via":null,"ats_vendor":"Recruitee","truth_index":{"grade":"B","score":75,"open_postings":11,"ghost_share":0,"stale_share":1,"repost_share":0,"time_to_fill_p50_days":null,"computed_at":"2026-10-12T06:55:09Z"}},"role":"Backend","role_family":"Backend","seniority":"senior","employment_type":"freelance","work_mode":"on_site","remote_scope":null,"remote_scope_basis":null,"remote_working_hours":null,"hiring_geo_confidence":"explicit","locations":["Warsaw, Poland"],"countries":["PL"],"hiring_countries":[],"hiring_countries_total":0,"salary":null,"salary_estimate":{"min_usd":56000,"max_usd":93000,"period":"year","method":"role_seniority_country_remote_cell","sample_n":312},"experience_years_min":8,"visa_sponsorship":false,"relocation_package":false,"has_equity":false,"technologies":[{"name":"Agile","optional":false},{"name":"ASP.NET Core","optional":false},{"name":"Azure","optional":false},{"name":"Azure DevOps","optional":false},{"name":"C#","optional":false},{"name":"Checkmarx","optional":false},{"name":"CI/CD","optional":false},{"name":"Entity Framework Core","optional":false},{"name":"Hangfire","optional":false},{"name":"OpenShift","optional":false},{"name":"Scrum","optional":false},{"name":"SQL","optional":false},{"name":"TypeScript","optional":false},{"name":"UML","optional":false},{"name":"Windows","optional":false}],"status":"live","first_seen_at":"2026-10-08T12:15:53Z","employer_posted_date":"2026-10-08","last_verified_at":"2026-10-12T06:05:03Z","board_verified":true,"closed_at":null,"days_open":4,"trust":{"level":"ok","repost_count":null,"flags":[],"days_open":4},"description":"NOTE: This job requires relocation to Poland or that you live within 2 hours radius of Warsaw, the location of the client premises. It is not fully remote, as the client may request for you to come on-site occasionally.\nWe are looking for an experienced Senior Full Stack .NET Developer / Technical Lead to contribute to the design, development, integration and ongoing support of enterprise-level web applications within a complex IT environment.\nThe successful candidate will combine strong hands-on development expertise with technical leadership capabilities, ensuring the delivery of scalable, secure and maintainable software solutions.\nThe role involves working closely with internal stakeholders, development teams and external technology partners, while taking technical ownership of applications throughout their lifecycle, from requirements analysis and solution design through to deployment, maintenance and production support.\nSoftware Development & Architecture\nDesign, develop and maintain enterprise web applications using C#, ASP.NET Core / .NET 8, Entity Framework and SQL Server.\n\nDevelop modern, responsive single-page applications using React and TypeScript.\n\nTranslate functional and business requirements into robust technical designs, using UML where appropriate.\n\nDesign and implement application components across the data, business logic and presentation layers.\n\nOptimize application performance, security, reliability and maintainability.\n\nContribute to software integration, prototyping, testing and quality assurance.\n\nTechnical Leadership & Delivery\nProvide technical guidance and leadership to development teams, promoting best practices and coding standards.\n\nParticipate in Agile/Scrum development activities, technical planning and effort estimation.\n\nConduct code reviews, identify technical debt and propose sustainable improvements.\n\nProduce and maintain clear technical documentation, solution designs and development specifications.\n\nCollaborate with external development partners to ensure effective knowledge transfer, application handover and technical continuity.\n\nDevOps, Deployment & Application Security\nManage application builds, deployments and release processes using Azure DevOps Pipelines.\n\nSupport application deployment and operations across Windows/IIS, virtualized and containerized environments, including Nutanix or OpenShift.\n\nImplement and maintain background-processing services using frameworks such as Hangfire.\n\nSupport application security mechanisms, including ASP.NET Core Data Protection, certificate management and identity federation.\n\nAddress vulnerabilities identified through security scanning, including Checkmarx, and penetration testing.\n\nApplication Integration & Production Support\nIntegrate enterprise applications with authentication and identity-management solutions, including SAML 2.0 and Microsoft Entra ID.\n\nDevelop and maintain integrations involving document-management systems, PDF generation and image-processing technologies.\n\nProvide second- and third-line application support, including incident investigation, troubleshooting and root-cause analysis.\n\nSupport user acceptance testing (UAT), change management and release coordination through established governance processes, including Change Advisory Boards (CAB).\n\nWork alongside third-party contractors during application transition and support periods to ensure operational stability and continuity.\n\nRequirements\nAt least 8 years working in this field of IT with at least 6 years specifically using the mentioned tools\n\nA certification in UML\n\nA certification in Software Development - related to .NET/Microsoft technologies (Azure/C# for example)\n\nStrong professional experience developing and supporting enterprise applications using C#,ASP.NETCore / .NET 8 and Entity Framework.\n\nProven front-end development experience with React and TypeScript.\n\nSolid knowledge of SQL Server, database design and application data management.\n\nHands-on experience with Azure DevOps, CI /CD pipelines and application release processes.\n\nUnderstanding of multi-tier application architecture, object-oriented design and UML modelling.\n\nExperience working in Agile / Scrum development environments.\n\nFamiliarity with application hosting and deployment on Windows/IIS and containerized or virtualized infrastructure.\n\nExperience with enterprise authentication, application security and secure development practices.\n\nDemonstrated ability to support production applications and resolve complex technical issues.","description_format":"text","description_chars":4542,"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":[],"hiring_locations":[{"name":"Poland","iso":"PL","kind":"country"}],"hiring_excludes":[],"relocation_offered":true,"industries":["Cybersecurity","Information Technology","Hospitals & Health Systems","Managed IT Services (MSP)"],"lifecycle":[{"event":"open","at":"2026-10-11T19:17:54Z"}],"visa":[],"liveness":{"score":60,"band":"ok","label":"Likely open","p_open":1,"p_active":0.602,"p_room":1,"age_days":3,"expected_fill_days":44,"reasons":["conf:0","stale_co","win:early"],"computed_at":"2026-10-12T06:55:09Z"},"pay":null,"html_url":"https://alion.io/job/keyes-senior-full-stack-developer-net-corereact-90-remote-poland","json_url":"https://alion.io/job/keyes-senior-full-stack-developer-net-corereact-90-remote-poland.json","meta":{"generated_at":"2026-10-12T13:20:47Z","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_verified","counted_by":"address","units_charged":1,"used_today":20805,"day_limit":null,"remaining_today":null,"minute_limit":300,"resets_at":"2026-10-13T00:00:00Z"}},"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":54374},"rest":"https://alion.io/mcp/rest/get_company?id=54374"},"human":"https://alion.io/catalog?offer=company.slices&for=job%2Fkeyes-senior-full-stack-developer-net-corereact-90-remote-poland"},{"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%2Fkeyes-senior-full-stack-developer-net-corereact-90-remote-poland"},{"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%2Fkeyes-senior-full-stack-developer-net-corereact-90-remote-poland"},{"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/keyes-senior-full-stack-developer-net-corereact-90-remote-poland\", \"note\": \"what you need it for\"}"},"human":"https://alion.io/catalog?offer=company.verify&for=job%2Fkeyes-senior-full-stack-developer-net-corereact-90-remote-poland"}]}