{"id":2069234,"url":"https://alion.io/job/langchain-senior-fullstack-software-engineer-ai-observability-evals-platform-ny","title":"Senior Fullstack Software Engineer, AI Observability & Evals Platform (NY)","company":{"id":4855,"name":"LangChain","domain":"langchain.com","url":"https://alion.io/company/langchain","size_band":"1001-5000","is_staffing_agency":false,"employer_type":"direct","is_intermediary":false,"listed_via":null,"ats_vendor":"Ashby","truth_index":{"grade":"A","score":90,"open_postings":51,"ghost_share":0,"stale_share":0.216,"repost_share":0,"time_to_fill_p50_days":68,"computed_at":"2026-10-10T05:45:15Z"}},"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":["San Francisco, United States"],"countries":["US"],"hiring_countries":[],"hiring_countries_total":0,"salary":{"min":180000,"max":240000,"currency":"USD","period":"year","gross":null,"usd_annual":240000},"salary_estimate":null,"experience_years_min":5,"visa_sponsorship":false,"relocation_package":false,"has_equity":false,"technologies":[{"name":"Cloudflare","optional":false},{"name":"Go","optional":false},{"name":"LangChain","optional":false},{"name":"LangGraph","optional":false},{"name":"LangSmith","optional":false},{"name":"LLM","optional":false},{"name":"Monday.com","optional":false},{"name":"PostgreSQL","optional":false},{"name":"Python","optional":false},{"name":"React.js","optional":false},{"name":"Redis","optional":false},{"name":"TypeScript","optional":false},{"name":"AI Agents","optional":true},{"name":"JavaScript","optional":true}],"status":"live","first_seen_at":"2026-10-08T04:05:32Z","employer_posted_date":"2026-10-08","last_verified_at":"2026-10-12T00:21:46Z","board_verified":true,"closed_at":null,"days_open":3,"trust":{"level":"ok","repost_count":null,"flags":[],"days_open":3},"description":"About Us\nAt LangChain, our mission is to make intelligent agents ubiquitous. We build the foundation for agent engineering in the real world, helping developers move from prototypes to production-ready AI agents that teams can rely on. We began as widely adopted open-source tools and have grown to also offer a platform for building, evaluating, deploying, and operating agents at scale.\nWith $125M raised at Series B from IVP, Sequoia, Benchmark, CapitalG, and Sapphire Ventures, we’re at a stage where we’re continuing to develop new products, growth is accelerating, and all team members have meaningful impact on what we build and how we work together. LangChain is a place where your contributions can shape how this technology shows up in the real world.\nToday, our platform includes LangSmith (Observability, Evaluation, Deployment, Fleet, and Sandboxes), our open source frameworks (LangChain, LangGraph, and Deep Agents), and the newly launched LangSmith Engine for autonomous agent improvement. We have 100M+ monthly open source downloads, 6,000+ active LangSmith customers, and 5 of the Fortune 10 use LangSmith in production (+ 35% of the Fortune 500 overall), including teams at Klarna, Clay, Coinbase, Workday, Lyft, Cloudflare, Harvey, Rippling, Vanta, LinkedIn, Monday.com, Nvidia, and Bridgewater.\nAbout the role:\nWe're looking for a Senior Fullstack Engineer for our commercial product LangSmith, an observability and evals platform. In this role, you'll have the opportunity to shape the technical direction of our platform while working closely with enterprise customers, developer end-users and internal stakeholders.\nWhat You Will Do:\nLead the technical architecture and implementation of key product features for LangSmith, working across our entire Go, Python, and Typescript stack.\n\nCollaborate closely with product and design teams to iterate on new features.\n\nMentor and guide more junior members of the team. Drive aggressive project timelines while ensuring high engineering standards are being met.\n\nLead by example in writing clean, maintainable, and well-tested code\n\nWhat You Bring:\n5+ years of experience in software engineering working on complex platform products\n\nFullstack engineering experience with Go or Python on the backend and React + Typescript on the frontend.\n\nStrong understanding of database systems, particularly Postgres and Redis\n\nExperience designing and scaling APIs, preferably in a high-performance, data-intensive application\n\nA “get stuff done” attitude - comfortable shipping fast and iterating based on user feedback\n\nStrong communicator with the ability to collaborate closely with various internal stakeholders and engage directly with our top-tier customers\n\nStrong ownership mindset\n\nBonus: Experience with AI/LLM-powered applications, developer tools, or observability platforms\n\nAnnual salary range: $180,000-$240,000 USD\nCompensation Philosophy:\nWe offer competitive compensation that includes base salary, variable compensation for relevant roles, meaningful equity, benefits, and perks. Actual compensation and offerings will vary based on role, level, and location. Team members in the EU, UK, and APAC receive locally competitive benefits aligned with regional norms and regulations.\nBenefits\nBenefits include medical, dental, and vision coverage, flexible vacation, a 401(k) plan, meals on in-office days in the US and more.","description_format":"text","description_chars":3397,"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":[]},"benefits":["Equity"],"hiring_locations":[{"name":"United States","iso":"US","kind":"country"}],"hiring_excludes":[],"relocation_offered":false,"industries":["Artificial Intelligence","LLM & Generative AI","AI Development Tools","AI Evaluation & Observability"],"lifecycle":[{"event":"open","at":"2026-10-08T05:37:06Z"}],"visa":[{"country":"US","licensed_sponsor":true,"evidence":"H-1B filings in 12 months: 17","filings_12m":17,"filings_prev_12m":2,"green_card_filings_12m":0,"median_offered_wage_usd":172500,"route":null,"cap_exempt":false,"checked_at":"2026-10-03T21:08:04+00:00","sources":["US Department of Labor: LCA disclosure data (H-1B, H-1B1, E-3)"],"filings_for_role_12m":15}],"liveness":{"score":90,"band":"hot","label":"Hiring now","p_open":1,"p_active":0.903,"p_room":1,"age_days":2,"expected_fill_days":68,"reasons":["conf:1","velocity","win:early","comp:brand"],"computed_at":"2026-10-10T05:45:15Z"},"pay":{"stated_usd_annual":240000,"is_top_pay":true},"html_url":"https://alion.io/job/langchain-senior-fullstack-software-engineer-ai-observability-evals-platform-ny","json_url":"https://alion.io/job/langchain-senior-fullstack-software-engineer-ai-observability-evals-platform-ny.json","meta":{"generated_at":"2026-10-12T03:18:43Z","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":5182,"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":4855},"rest":"https://alion.io/mcp/rest/get_company?id=4855"},"human":"https://alion.io/catalog?offer=company.slices&for=job%2Flangchain-senior-fullstack-software-engineer-ai-observability-evals-platform-ny"},{"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%2Flangchain-senior-fullstack-software-engineer-ai-observability-evals-platform-ny"},{"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%2Flangchain-senior-fullstack-software-engineer-ai-observability-evals-platform-ny"},{"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/langchain-senior-fullstack-software-engineer-ai-observability-evals-platform-ny\", \"note\": \"what you need it for\"}"},"human":"https://alion.io/catalog?offer=company.verify&for=job%2Flangchain-senior-fullstack-software-engineer-ai-observability-evals-platform-ny"}]}