{"id":36350,"url":"https://alion.io/job/flagshippioneering-principal-senior-software-engineer","title":"Principal / Senior Software Engineer","company":{"id":8393,"name":"Flagship Pioneering","domain":"flagshippioneering.com","url":"https://alion.io/company/flagshippioneering","size_band":"1001-5000","is_staffing_agency":false,"employer_type":"direct","is_intermediary":true,"listed_via":null,"ats_vendor":"Greenhouse","truth_index":{"grade":"B","score":79,"open_postings":10,"ghost_share":0,"stale_share":0.8,"repost_share":0.1,"time_to_fill_p50_days":50,"computed_at":"2026-10-29T05:49:05Z"}},"role":"Backend","role_family":"Backend","seniority":"lead","employment_type":null,"work_mode":"on_site","remote_scope":null,"remote_scope_basis":null,"remote_working_hours":null,"hiring_geo_confidence":"explicit","locations":["Cambridge, United States"],"countries":["US"],"hiring_countries":[],"hiring_countries_total":0,"salary":{"min":108000,"max":209000,"currency":"USD","period":"year","gross":null,"usd_annual":209000},"salary_estimate":null,"experience_years_min":5,"visa_sponsorship":false,"relocation_package":false,"has_equity":false,"technologies":[{"name":"Amazon ECS","optional":false},{"name":"Amazon S3","optional":false},{"name":"AWS","optional":false},{"name":"AWS Lambda","optional":false},{"name":"CI/CD","optional":false},{"name":"Machine Learning","optional":false},{"name":"Python","optional":false},{"name":"AWS CDK","optional":true},{"name":"LLM","optional":true},{"name":"TypeScript","optional":true}],"status":"live","first_seen_at":"2026-07-30T15:58:14Z","employer_posted_date":"2026-10-06","last_verified_at":"2026-10-29T15:51:46Z","board_verified":true,"closed_at":null,"days_open":91,"trust":{"level":"ok","repost_count":null,"flags":[],"days_open":91},"description":"The Company \nIris Labs, Inc. is a privately held, early-stage company pioneering the use of artificial intelligence to transform how people navigate life’s challenges and wellbeing. We are creating a platform that empowers people to build a life they are proud of and fulfilled by. We bring together psychology, product, design, engineering, and machine learning to build digital experiences that are engaging, trustworthy, and genuinely helpful. \nIris Labs is backed by Flagship Pioneering, an innovation enterprise that conceives, creates, resources, and builds companies that invent breakthrough technologies that transform the world. Flagship has created over 100 groundbreaking companies since 2000, including Moderna. \nThe Role \nWe are seeking an experienced, creative, and talented Principal / Senior Software Engineer. The ideal candidate will have a strong background in software and product development, with the ability to lead projects and communicate effectively across teams and with ML researchers. \nKey Responsibilities \nLead the design and development of customer-facing features across the front-end and back-end application stack. \nPartner closely with product managers, designers, and researchers to translate customer needs and product strategy into well-designed, high-impact features. \nOwn features throughout the full product development lifecycle, from discovery and technical design through implementation, release, measurement, and iteration. \nManage the release process for new features, including rollout planning, feature flagging, monitoring, and coordination across engineering and product teams. \nUse product analytics, feature experiments, and customer feedback to evaluate feature performance and guide continued development. \nDesign scalable system architecture for rapidly evolving, AI-enabled back-end components. \nContribute to user interface and interaction design, bringing technical insight into product and design decisions. \nImprove application delivery practices by implementing continuous integration, continuous delivery, automated testing, and operational best practices. \nLeverage AWS cloud infrastructure to build scalable, reliable, and efficient applications and AI-powered services. \nUphold high standards of data security, privacy, and compliance across all applications. \nSuccessful candidates will be able to thrive in a fast-paced, action-oriented, team environment and display a clear passion for AI innovation and impact. The role offers a unique opportunity to help drive the strategy of an early stage AI-focused company. The candidate must be an entrepreneurial, highly motivated, and purpose-driven individual. The successful candidate will have a track record of building consumer applications or large internal applications. They must exhibit strong collaboration and communication skills. They should be ready to lead application development in a very dynamic and innovative environment. \nQualifications: \n5+ years of experience in software development, with a strong focus on building applications. \nExtensive experience with AWS services (including ECS, S3, Lambda, etc) or a similar cloud services provider. \nProficient in Python. \nDemonstrated ability to build scalable, efficient, and secure software applications. \nMotivated and team oriented, with an ability to thrive in a multidisciplinary environment. \nExcellent communication and collaboration abilities.\nPreferred Qualifications: \nExperience with LLM development. \nAWS Certifications, such as Solutions Architect Associate or Professional. \nAble to build applications using the AWS CDK and Typescript. \nKnowledge of security best practices for SaaS solutions. \nAbout Flagship \nFlagship Pioneering is a bioplatform innovation company that invents and builds platform companies, each with the potential for multiple products that transform human health or sustainability. Since its launch in 2000, Flagship has originated and fostered more than 100 scientific ventures, resulting in more than $90 billion in aggregate value. Many of the companies Flagship has founded have addressed humanity’s most urgent challenges: vaccinating billions of people against COVID-19, curing intractable diseases, improving human health, preempting illness, and feeding the world by improving the resiliency and sustainability of agriculture. Flagship has been recognized twice on FORTUNE’s “Change the World” list, an annual ranking of companies that have made a positive social and environmental impact through activities that are part of their core business strategies, and has been twice named to Fast Company’s annual list of the World’s Most Innovative Companies. Learn more about Flagship at www.flagshippioneering.com. \nFlagship Pioneering and our ecosystem companies are committed to equal employment opportunity regardless of race, color, ancestry, religion, sex, national origin, sexual orientation, age, citizenship, marital status, disability, gender identity or Veteran status. \nAt Flagship, we recognize there is no perfect candidate. If you have some of the experience listed above but not all, please apply anyway. Experience comes in many forms, skills are transferable, and passion goes a long way. We are dedicated to building diverse and inclusive teams and look forward to learning more about your unique background. \nRecruitment & Staffing Agencies: Flagship Pioneering and its affiliated Flagship Lab companies (collectively, “FSP”) do not accept unsolicited resumes from any source other than candidates. The submission of unsolicited resumes by recruitment or staffing agencies to FSP or its employees is strictly prohibited unless contacted directly by Flagship Pioneering’s internal Talent Acquisition team. Any resume submitted by an agency in the absence of a signed agreement will automatically become the property of FSP, and FSP will not owe any referral or other fees with respect thereto. \nThe salary range for this role is $108,000 - $209,000. Compensation for the role will depend on a number of factors, including a candidate’s qualifications, skills, competencies, and experience. Iris Labs, Inc. currently offers healthcare coverage, annual incentive program, retirement benefits and a broad range of other benefits. Compensation and benefits information is based on Iris Labs, Inc.'s good faith estimate as of the date of publication and may be modified in the future.\nPrivacy Notice for Applicants: When you apply for a role at Flagship Pioneering or one of its portfolio companies, we collect and use personal information you provide (such as your name, contact details, work history, and application materials) to evaluate your application, communicate with you, and comply with legal obligations. Your application data is processed through Greenhouse, our applicant tracking system, and may also be reviewed using AI-assisted screening tools. We do not sell your personal information. California residents have rights under the CCPA/CPRA including to know, delete, and opt out of the sharing of their personal information. If you are located in the EU or UK, we process your data under GDPR and you have rights to access, rectify, and erase your data. To exercise your rights or for questions, contact .","description_format":"text","description_chars":7286,"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":[],"hiring_locations":[{"name":"United Kingdom","iso":"GB","kind":"country"}],"hiring_excludes":[],"relocation_offered":false,"industries":["Venture Capital"],"lifecycle":[{"event":"open","at":"2026-07-30T15:58:14Z"},{"event":"close","at":"2026-09-22T14:04:20Z"},{"event":"reopen","at":"2026-09-22T19:59:57Z"}],"visa":[{"country":"US","licensed_sponsor":true,"evidence":"H-1B filings in 12 months: 10 · green card filings: 2","filings_12m":10,"filings_prev_12m":3,"green_card_filings_12m":2,"median_offered_wage_usd":150833,"route":null,"cap_exempt":false,"checked_at":"2026-10-29T16:27:21+00:00","sources":["US Department of Labor: LCA disclosure data (H-1B, H-1B1, E-3)","US Department of Labor: PERM disclosure data (green cards)"],"filings_for_role_12m":1}],"liveness":{"score":17,"band":"cold","label":"Long shot","p_open":1,"p_active":0.465,"p_room":0.36,"age_days":90,"expected_fill_days":50,"reasons":["conf:3","stale_co","velocity","win:tail","crowd:"],"computed_at":"2026-10-29T05:49:05Z"},"pay":{"stated_usd_annual":209000,"is_top_pay":true},"html_url":"https://alion.io/job/flagshippioneering-principal-senior-software-engineer","json_url":"https://alion.io/job/flagshippioneering-principal-senior-software-engineer.json","meta":{"generated_at":"2026-10-29T17:33:33Z","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":26218,"day_limit":null,"remaining_today":null,"minute_limit":300,"resets_at":"2026-10-30T00:00:00Z"}},"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":8393},"rest":"https://alion.io/mcp/rest/get_company?id=8393"},"human":"https://alion.io/catalog?offer=company.slices&for=job%2Fflagshippioneering-principal-senior-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%2Fflagshippioneering-principal-senior-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%2Fflagshippioneering-principal-senior-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/flagshippioneering-principal-senior-software-engineer\", \"note\": \"what you need it for\"}"},"human":"https://alion.io/catalog?offer=company.verify&for=job%2Fflagshippioneering-principal-senior-software-engineer"}],"agent":{"mcp":"https://alion.io/mcp/jobs","mcp_open":"https://alion.io/mcp/open","next":[{"tool":"get_job","arguments":{"id":36350}},{"tool":"search_jobs","arguments":{"company":"flagshippioneering.com","detail":"compact"}},{"tool":"match_people","arguments":{"job_id":36350},"note":"people open to offers who fit this vacancy"}],"note":"The same data through MCP tools: https://alion.io/mcp/open needs no sign-in (compact searches, postings, people); https://alion.io/mcp with an Alion account has everything. Docs: https://alion.io/developers"}}