{"id":2087620,"url":"https://alion.io/job/outerlimit-senior-backend-engineer","title":"Senior Backend Engineer","company":{"id":3799759,"name":"Outer Limit","domain":"outerlimit.com","url":"https://alion.io/company/outerlimit","size_band":"51-200","is_staffing_agency":false,"employer_type":"direct","is_intermediary":false,"listed_via":null,"ats_vendor":"BambooHR","truth_index":null},"role":"Backend","role_family":"Backend","seniority":"senior","employment_type":"full_time","work_mode":"on_site","remote_scope":null,"remote_scope_basis":null,"remote_working_hours":null,"hiring_geo_confidence":"structured","locations":["London, United Kingdom"],"countries":["GB"],"hiring_countries":[],"hiring_countries_total":0,"salary":null,"salary_estimate":{"min_usd":91000,"max_usd":174000,"period":"year","method":"role_seniority_country_remote_cell","sample_n":125},"experience_years_min":5,"visa_sponsorship":false,"relocation_package":false,"has_equity":false,"technologies":[{"name":"AI Agents","optional":false},{"name":"Auth0","optional":false},{"name":"AWS","optional":false},{"name":"Azure","optional":false},{"name":"C#","optional":false},{"name":"CI/CD","optional":false},{"name":"Okta","optional":false},{"name":"SQL","optional":false},{"name":"Claude","optional":true},{"name":"Copilot","optional":true},{"name":"Cursor","optional":true},{"name":"LLM","optional":true}],"status":"live","first_seen_at":"2026-10-07T00:00:00Z","employer_posted_date":"2026-10-07","last_verified_at":"2026-10-16T20:44:29Z","board_verified":true,"closed_at":null,"days_open":9,"trust":{"level":"ok","repost_count":null,"flags":[],"days_open":9},"description":"About the role\nWe are looking for a Senior Backend Engineer to design and build core platform capabilities that underpin real-time control, security, and observability for agentic systems.\nThis is not a narrowly scoped feature role. This is for someone who can:\nDesign and implement high-performance backend services that sit in critical execution paths\nBuild systems that handle request/response flows, enforcement logic, and real-time decisioning\nWork with authentication and authorisation protocols (e.g. OAuth) to securely manage identity and access\nDevelop integrations with external systems, including identity providers and third-party platforms\nWrite efficient, reliable code that performs under load and supports low-latency requirements\nContribute to system design across multiple parts of the platform as the product evolves\nEnsure security, correctness, and observability are built into all layers of the system\nThis role is built for a strong mid-level engineer who is ready to make the step up to senior. You will contribute directly to core product capabilities and architectural direction, take growing ownership of system design, and be supported to become a senior technical voice in the team. Working as part of a high-calibre engineering team, you will thrive in a fast-paced environment where performance, reliability, and clean design are critical.\nWhat you’ll bring\nExperience\n5+ years' professional software engineering experience, including building production-grade backend systems\nAt least one tenure of 2+ years at a relatively large or established technology company\nCurrently a strong mid-level engineer with a clear track record of owning features end to end, now looking to step up to senior\nExperience working on systems in the request path (e.g. APIs, gateways, middleware, or similar)\nStrong ownership mentality and ability to operate with incomplete requirements\nPragmatic decision-maker who balances speed with long-term maintainability\nWillingness to support and mentor other engineers as you grow into a senior role\nA BSc in Computer Science is preferred; degrees in Mathematics, Physics or Engineering are also welcome\nBackend Systems & Architecture\nExperience designing and building scalable backend services\nStrong understanding of distributed systems concepts such as latency, throughput, and fault tolerance\nFamiliarity with handling high-throughput or low-latency systems\nExperience building systems that are observable, reliable, and secure\nAuthentication & Integrations\nStrong understanding of authentication and authorisation protocols (OAuth, OIDC, etc.)\nExperience integrating with identity providers (e.g. Okta, Azure AD, Auth0) or similar external systems\nUnderstanding of secure session handling, token validation, and access control\nProgramming\nStrong commercial experience with .NET (C#) and SQL, using modern engineering practices\nHands-on experience building and running services on Azure or AWS\nExperience writing performant, production-quality code\nUnderstanding of testing, CI/CD, and software engineering best practices\nReliability & Security\nExperience building systems that operate reliably under load\nStrong understanding of secure coding practices and backend security principles\nAwareness of common vulnerabilities in authentication flows and API systems\nNice to have\nAI tools\nExperience with Copilot, Cursor, Claude, or similar AI-assisted development tools\nAI systems\nExposure to LLM-powered systems, agent frameworks, or tool orchestration patterns\nInterest in how agent actions and execution context can be structured for analysis\nHow we work\nSmall, dynamic, high-calibre team\nIncomplete requirements are normal; shaping solutions is part of the job\nCode quality, consistency, and architecture are considered at the earliest phase of design to avoid accumulation of technical debt\nClose collaboration between frontend, backend, ML, DevOps and platform engineers\nThis is a role for someone who wants impact, ownership and intellectual challenge.\nAbout us\nEvery generational shift in computing requires a new layer of security infrastructure. In today's agentic era, Outerlimit provides the world's first decentralised security and authorisation layer designed specifically for securing Agentic AI.\nWe are backed by Evolution Equity Partners, AlbionVC and Crane Venture Partners, and our founding team has a proven track record of defining AI security landscapes, building market-leading security products and scaling businesses from startup to scale-up to exit.\nOur values\nSeek the truth: We're deeply curious, and we don't settle for the easy answer. Clarity beats comfort.\nWe own it:No job too small, no job too big. If it needs doing, we don't wait to be asked.\nNever complacent:Good enough today isn't good enough tomorrow. We aspire to relentless improvement.\nDo the right thing: Especially when it's hard, when no one's watching, and under pressure.\nWhy join Outerlimit\nReal ownership: meaningful equity for everyone. When Outerlimit wins, you win.\nTop-of-market pay, matched by benefits built to attract the best.\nFlagship offices in London King's Cross and New York City, with flexibility in how you work.\nThe whole team together in one room at least quarterly.\nA real budget for conferences, courses, books and gear.","description_format":"text","description_chars":5294,"description_truncated":false,"requirements":{"experience_years_min":5,"management_years_min":null,"team_size_min":null,"manages_managers":false,"education":{"level":"bachelor","optional":false},"security_clearance":false,"languages":[]},"benefits":["Equity"],"hiring_locations":[],"hiring_excludes":[],"relocation_offered":false,"industries":["Artificial Intelligence","AI Agents","Cybersecurity AI"],"lifecycle":[{"event":"open","at":"2026-10-08T13:03:27Z"}],"visa":[{"country":"GB","licensed_sponsor":true,"evidence":"Licensed UK visa sponsor (Skilled Worker)","filings_12m":null,"filings_prev_12m":null,"green_card_filings_12m":null,"median_offered_wage_usd":null,"route":"Skilled Worker","cap_exempt":false,"checked_at":"2026-10-16T06:21:30+00:00","sources":["UK Home Office: register of licensed sponsors (workers)"],"filings_for_role_12m":0}],"liveness":{"score":87,"band":"hot","label":"Hiring now","p_open":1,"p_active":0.865,"p_room":1,"age_days":9,"expected_fill_days":38,"reasons":["conf:2","velocity","win:early"],"computed_at":"2026-10-16T05:45:00Z"},"pay":null,"html_url":"https://alion.io/job/outerlimit-senior-backend-engineer","json_url":"https://alion.io/job/outerlimit-senior-backend-engineer.json","meta":{"generated_at":"2026-10-16T20:46:29Z","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":1490,"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":3799759},"rest":"https://alion.io/mcp/rest/get_company?id=3799759"},"human":"https://alion.io/catalog?offer=company.slices&for=job%2Fouterlimit-senior-backend-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%2Fouterlimit-senior-backend-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%2Fouterlimit-senior-backend-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/outerlimit-senior-backend-engineer\", \"note\": \"what you need it for\"}"},"human":"https://alion.io/catalog?offer=company.verify&for=job%2Fouterlimit-senior-backend-engineer"}]}