{"id":594230,"url":"https://alion.io/job/janestreet-dev-software-engineer-3","title":"Software Engineer","company":{"id":7349,"name":"Jane Street","domain":"janestreet.com","url":"https://alion.io/company/jane-street","size_band":"1001-5000","is_staffing_agency":false,"employer_type":"direct","is_intermediary":false,"listed_via":null,"ats_vendor":"Greenhouse","truth_index":{"grade":"B","score":75,"open_postings":169,"ghost_share":0.337,"stale_share":0,"repost_share":0,"time_to_fill_p50_days":141,"computed_at":"2026-10-17T05:46:00Z"}},"role":"Backend","role_family":"Backend","seniority":null,"employment_type":null,"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":74000,"max_usd":181000,"period":"year","method":"role_country_seniority_unknown","sample_n":383},"experience_years_min":null,"visa_sponsorship":false,"relocation_package":false,"has_equity":false,"technologies":[{"name":"Machine Learning","optional":false},{"name":"OCaml","optional":false},{"name":"Python","optional":false}],"status":"live","first_seen_at":"2026-08-07T15:36:42Z","employer_posted_date":"2026-09-28","last_verified_at":"2026-10-18T00:08:43Z","board_verified":true,"closed_at":null,"days_open":71,"trust":{"level":"ok","repost_count":0,"flags":["company_stale"],"days_open":70},"description":"About the Position\nWe’re looking for Software Engineers who want to help us design and build the systems and tools that run the firm. You’ll find Software Engineers in all parts of Jane Street, solving real problems in critical areas ranging from trading desks to our accounting team, as well as building foundational infrastructure, whether that means implementing network monitoring or risk models. \nWe are big believers in functional programming and, using OCaml, a statically -typed functional programming language, as our primary tool. More recently, Python has become a vital part of Jane Street’s research and trading work, acting as the go-to language for data analysis, visualization, and machine learning. \nBeyond our own environment, we also recognize the value of open source software, leveraging it in our daily work and releasing over a million lines of our own code as open source. We’re also always looking for ways to expand open source projects, and provide ongoing support to things like Mercurial, the OCaml compiler, and the OPAM package manager. That said, we’re interested in talented engineers with experience in any language-most of us came in with little to no practical experience in OCaml before we joined.\nIf you’d like to learn more, you can read about our interview process and meet some of our newest hires.\nAbout You\nWe don’t expect you to have a background in functional programming, OCaml, Python, finance, or any other specific field-we’re looking for smart programmers who enjoy solving interesting problems. We’re more interested in how you think and learn than what you currently know. You should be:\nA top-notch programmer with a love for technology\nIntellectually curious, collaborative, and eager to learn\nHumble and unafraid to ask questions and admit mistakes\nFluent in English\nIf you'd like to get an idea of what we cover in our software engineering interview process, you can visit our interview prep page.\nIf you're a recruiting agency and want to partner with us, please reach out to .","description_format":"text","description_chars":2068,"description_truncated":false,"requirements":{"experience_years_min":null,"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":[],"hiring_locations":[],"hiring_excludes":[],"relocation_offered":false,"industries":["Hedge Funds & Alternative Investments"],"lifecycle":[{"event":"open","at":"2026-09-10T14:59:02Z"}],"visa":[{"country":"GB","licensed_sponsor":true,"evidence":"Licensed UK visa sponsor (Senior or Specialist Worker, Skilled Worker)","filings_12m":null,"filings_prev_12m":null,"green_card_filings_12m":null,"median_offered_wage_usd":null,"route":"Global Business Mobility: Senior or Specialist Worker; Skilled Worker","cap_exempt":false,"checked_at":"2026-10-17T06:21:15+00:00","sources":["UK Home Office: register of licensed sponsors (workers)"],"filings_for_role_12m":0}],"liveness":{"score":58,"band":"ok","label":"Likely open","p_open":1,"p_active":0.801,"p_room":0.72,"age_days":70,"expected_fill_days":141,"reasons":["conf:0","velocity","win:mid","crowd:brand"],"computed_at":"2026-10-17T05:46:00Z"},"pay":null,"html_url":"https://alion.io/job/janestreet-dev-software-engineer-3","json_url":"https://alion.io/job/janestreet-dev-software-engineer-3.json","meta":{"generated_at":"2026-10-18T02:51:52Z","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":4523,"day_limit":null,"remaining_today":null,"minute_limit":300,"resets_at":"2026-10-19T00:00:00Z"}},"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":7349},"rest":"https://alion.io/mcp/rest/get_company?id=7349"},"human":"https://alion.io/catalog?offer=company.slices&for=job%2Fjanestreet-dev-software-engineer-3"},{"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%2Fjanestreet-dev-software-engineer-3"},{"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%2Fjanestreet-dev-software-engineer-3"},{"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/janestreet-dev-software-engineer-3\", \"note\": \"what you need it for\"}"},"human":"https://alion.io/catalog?offer=company.verify&for=job%2Fjanestreet-dev-software-engineer-3"}]}