{"id":155624,"url":"https://alion.io/job/fourthline-senior-backend-software-engineer","title":"Senior Backend Software Engineer","company":{"id":54568,"name":"Fourthline","domain":"fourthline.com","url":"https://alion.io/company/fourthline","size_band":"201-500","is_staffing_agency":false,"employer_type":"direct","is_intermediary":false,"listed_via":null,"ats_vendor":"Greenhouse","truth_index":{"grade":"B","score":75,"open_postings":3,"ghost_share":0,"stale_share":1,"repost_share":0,"time_to_fill_p50_days":null,"computed_at":"2026-10-16T05:45:00Z"}},"role":"Backend","role_family":"Backend","seniority":"senior","employment_type":null,"work_mode":"hybrid","remote_scope":null,"remote_scope_basis":null,"remote_working_hours":null,"hiring_geo_confidence":"structured","locations":["Barcelona, Spain"],"countries":["ES"],"hiring_countries":[],"hiring_countries_total":0,"salary":null,"salary_estimate":{"min_usd":48000,"max_usd":103000,"period":"year","method":"role_seniority_country_remote_cell","sample_n":25},"experience_years_min":5,"visa_sponsorship":false,"relocation_package":false,"has_equity":false,"technologies":[{"name":".NET","optional":false},{"name":"C#","optional":false},{"name":"Rest API","optional":false},{"name":"Amazon EKS","optional":true},{"name":"AWS","optional":true},{"name":"Azure","optional":true},{"name":"Azure DevOps","optional":true},{"name":"CI/CD","optional":true},{"name":"Docker","optional":true},{"name":"Git","optional":true},{"name":"Kubernetes","optional":true},{"name":"PostgreSQL","optional":true},{"name":"RabbitMQ","optional":true},{"name":"Terraform","optional":true}],"status":"live","first_seen_at":"2026-02-11T15:51:27Z","employer_posted_date":"2026-08-05","last_verified_at":"2026-10-16T14:52:39Z","board_verified":true,"closed_at":null,"days_open":247,"trust":{"level":"stale","repost_count":0,"flags":["stale"],"days_open":246},"description":"At Fourthline, our mission is to fight financial crime. We help protect the global financial system by verifying millions of identities for banks, neobanks, online brokers, crypto exchanges, and insurers like N26, Trade Republic, flatexDEGIRO, Nationale Nederlanden, Qonto, Shine, Solarisbank, and more.\nHaving started our journey in January 2018, we're incredibly proud to count around 250 employees between our Amsterdam and Barcelona offices with over 50 nationalities.\nPrevent financial crime by building best-in-class SaaS solutions with our talented Anti-Money Laundering (AML) and Bank Account Verification (BAV) + Qualified Electronic Signatures (QES) teams in Barcelona -we’re looking for a Senior Backend Software Engineer who brings solid technical expertise, a product-driven mindset, and a collaborative spirit across diverse domains and skill levels. \nAs a senior backend engineer at Fourthline, you will: \nDesign, develop, maintain, and improve our microservices, and take responsibility for thorough testing and reliable deployments of your stories. \nProfessionally manage your tasks, priorities and deliverables, taking joint ownership with your teammates for the sprint goals. \nUtilize your experience to contribute to our growth through lessons learned from your successes and failures. \nTake responsibility for engineering excellence and participate in architectural decision-making within your team. \nContribute to thorough documentation-crucial for ensuring success and minimizing questions! \nUnderstand the entire development lifecycle and work closely with other members in squads, including Platform and QA teams. \nEmploy both technical and soft skills to address challenges, recognizing that solutions often require a blend of technology-based and people-based strategies. \nEmphasis on Collaboration \nAt Fourthline, we foster a collaborative culture informed by industry knowledge (FinTech) and deep understanding of our business objectives. You will actively participate in chapter meetings, knowledge sharing sessions and cross-discipline alignments with other teams and engineering disciplines. \nCareer Growth and Development \nAt Fourthline, we offer opportunities for learning and development, allowing you to work alongside and learn from experienced engineers. As you grow within our team, there are possibilities to grow to Staff Engineer level and beyond, with clear pathways to further your technical, problem solving and communication competencies, as well as build your knowledge of the FinTech industry. \nOur Stack \n.NET 5-8 - Our cloud-based microservices architecture includes REST APIs, Docker, Message Queues (RabbitMQ), RDBMS (PostgreSQL), Wolverine, Marten (Doc + Event stores), and much more! \nJob Requirements \nMinimum 5 years software development experience in one or more general-purpose programming languages. \nGood knowledge of .NET 5-8, or .NET Core 3.x \nProficiency in C# (version 10 or later). \nExperience in unit and integration testing with XUnit (MSTest/NUnit are a plus). \nFamiliarity with ORMs (EF Core) and knowledge of Linq. \nExperience implementing REST APIs using .NET Web API. \nUnderstanding of SOLID principles and Domain-Driven Design (DDD). \nKnowledge of common software design patterns. \nExperience with Git and CI/CD in Azure DevOps. \nExperience with cloud providers such as AWS and Azure; experience with EKS and Terraform is highly valued. \nAbility to work on-site at our fantastic office in Barcelona at least 3 days a week as per our Hybrid Working Policy. \nLanguage skills: English full professional proficiency. \nAt Fourthline, we believe diversity enriches our culture and inspires you to do your best work. We value your unique talents and perspectives, welcoming them into a safe and inclusive working environment, to ultimately deliver the best products to our customers and society. You're welcome here. Fourthline is for everyone.\nOur hiring process is designed to be equal, fair, and transparent. We welcome people from all backgrounds, ethnicities, genders, sexual orientations, ages, abilities, religions, and experiences in life. If you're excited about this role, but your experience does not align perfectly with every qualification in the job description, we encourage you to apply anyways. You may just be the right candidate for this or other roles.","description_format":"text","description_chars":4338,"description_truncated":false,"requirements":{"experience_years_min":5,"management_years_min":null,"team_size_min":null,"manages_managers":false,"education":null,"security_clearance":false,"languages":[{"language":"English","level":"Advanced (C1)","optional":false}]},"benefits":["Hybrid work"],"hiring_locations":[{"name":"Spain","iso":"ES","kind":"country"}],"hiring_excludes":[],"relocation_offered":false,"industries":["Identity Management","RegTech, AML & Compliance"],"lifecycle":[{"event":"open","at":"2026-02-11T15:51:27Z"}],"visa":[],"liveness":{"score":9,"band":"cold","label":"Long shot","p_open":1,"p_active":0.334,"p_room":0.28,"age_days":246,"expected_fill_days":37,"reasons":["conf:0","win:tail","crowd:"],"computed_at":"2026-10-16T05:45:00Z"},"pay":null,"html_url":"https://alion.io/job/fourthline-senior-backend-software-engineer","json_url":"https://alion.io/job/fourthline-senior-backend-software-engineer.json","meta":{"generated_at":"2026-10-16T18:45:00Z","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":4051,"day_limit":null,"remaining_today":null,"minute_limit":300,"resets_at":"2026-10-17T00:00:00Z"}},"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":54568},"rest":"https://alion.io/mcp/rest/get_company?id=54568"},"human":"https://alion.io/catalog?offer=company.slices&for=job%2Ffourthline-senior-backend-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%2Ffourthline-senior-backend-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%2Ffourthline-senior-backend-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/fourthline-senior-backend-software-engineer\", \"note\": \"what you need it for\"}"},"human":"https://alion.io/catalog?offer=company.verify&for=job%2Ffourthline-senior-backend-software-engineer"}]}