Principal Engineer

Principal EngineerCambridge, MA USAPioneering Intelligence builds on Flagship Pioneering's legacy of founding cutting-edge science and computational ventures, harnessing recent advances in AI, machine learning, and data to accelerate fundamental research and create a portfolio of AI-first companies. As part of Flagship's integrated model of science, entrepreneurship, and capital, it transforms breakthrough ideas into world-changing companies, elevating the AI advances happening across the ecosystem in human health, sustainability, and beyond.Pioneering Intelligence is looking for a Principal Software Engineer to join a small, senior team building the digital and AI platform that powers drug discovery and scientific research across the Flagship Pioneering ecosystem. This is a senior individual contributor role that will report directly to the Vice President of Engineering and operate as the technical authority for one or more product areas — designing systems end-to-end, building hands-on, and engaging directly with the scientists, ML researchers, and strategists who use what you build.This is not a role for engineers who want to be shielded from ambiguity or who need a product manager to translate user needs into tasks. You will own the full technical stack for your product area: from understanding what scientists actually need, through system design and data architecture, to deployment and ongoing reliability. You will work in close partnership with product leadership and ML scientists, but the technical decisions are yours to make and yours to own.The team model is intentionally lean. Each Principal Engineer on this team is a full technical lead for their domain, not one of several engineers on a layered team. You may from time to time coordinate the work of embedded software engineering contractors, but your primary contribution is your own engineering output and technical judgment. The VP of Engineering will set strategy and remove organizational blockers; the work itself is yours.Key responsibilities include:Own the technical architecture and implementation for one or more AI-powered product areas within the Pioneering Intelligence platform, including scientific workflow tools, data infrastructure, and agentic AI systemsDesign and build production-grade systems end-to-end: from data models and API contracts through deployment, observability, and long-term maintainabilityEngage directly with scientific, clinical, and ML users to understand what they actually need — not what they ask for — and translate that understanding into software that advances their workMake the highest-stakes technical decisions in your domain: system architecture, build-vs-buy tradeoffs, integration patterns for AI and ML components, and data pipeline designCollaborate closely with product and ML science counterparts, contributing technical perspective to product strategy and helping shape what gets built before a single line of code is writtenParticipate in architectural reviews across the broader engineering team, raising the collective bar and identifying cross-cutting concerns before they become problemsUse AI-native engineering tools — including Claude Code and similar — as genuine force multipliers in your daily practice, not as noveltiesWhen project needs require it, coordinate the work of fully embedded software engineering contractors, providing technical direction and maintaining quality standardsProfessional experience and qualifications include:Has served as the technical authority on a complex, production-grade system — not as a manager who delegates the hard parts, but as an engineer who owned the architecture and the most difficult implementation decisionsHas built software that is actively used by researchers, scientists, or other domain experts to make consequential decisions, and understands how the needs of expert users differ from those of general operatorsHas designed and shipped systems that include ML or AI components — whether LLM-powered workflows, model inference infrastructure, or agentic pipelines — in a production settingHas operated effectively in ambiguous, fast-moving environments where requirements evolve and the right technical direction is not handed down from aboveHas worked closely with ML scientists or research teams to bridge the gap between experimental models and reliable production softwareSkills include:Technically credible at the system design level: can evaluate architectural options, identify failure modes in complex distributed systems, and make principled decisions about tradeoffs between reliability, performance, and maintainabilityFluent in AI-native engineering: understands LLM capabilities and limitations, can design reliable orchestration layers for agentic workflows, and knows when AI is the right tool and when it is notEngineering craft: writes clean, well-tested, well-documented code and reviews others' work at a level that raises quality without creating friction or slowing deliveryWrites with precision: technical design documents, architecture reviews, and API contracts that create clarity for collaborators rather than requiring follow-upDebugging and root-cause analysis: finds the real source of production failures, distinguishes symptoms from causes, and fixes problems at the right level of abstractionTraits include:Technically deep and domain-curious: genuinely interested in the scientific and clinical problems the platform is solving, not just the engineering challenges they surfaceHigh standards, low ego: holds their own work — and others' — to an exceptional bar without creating friction, and finds it satisfying to make a codebase better rather than just largerFounder-minded: attracted to ambiguity, motivated by impact, and able to build a coherent technical direction from unclear requirements without waiting for full specificationDirect and decisive: makes technical calls with available information, owns the outcomes, and communicates tradeoffs clearly to non-engineering stakeholdersMultiplier: makes the engineers and scientists around them more effective through thoughtful technical leadership, clear documentation, and a genuine investment in shared qualityWhy Pioneering Intelligence?Own the technical architecture of a product area that matters: your systems will be used by scientists making decisions that shape the future of medicineWork on genuinely hard engineering problems at the intersection of agentic AI, scientific data, and high-stakes decision-makingOperate with principal-level autonomy in a lean team where the floor is exceptional and the work speaks for itselfUse state-of-the-art AI tools as a core part of your engineering practice — not as an experiment, but as how the team buildsCollaborate with world-class scientists, ML researchers, and builders across the Flagship Pioneering ecosystemCompetitive compensation and benefits, including equity, commensurate with experienceFlagship Pioneering invents and builds platform companies, each with the potential for multiple products that transform human health, sustainability and beyond. Since its launch in 2000, Flagship has originated more than 100 companies. Many of these companies 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 and has been twice named to Fast Company's annual list of the World's Most Innovative Companies.We are an equal opportunity employer. All qualified applicants will be considered for employment without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, disability, protected veteran status, or any other characteristic protected by law.We recognize that great candidates often bring unique strengths without fulfilling every qualification. If you have some of the experience listed above but not all, please apply anyway. We are dedicated to building diverse and inclusive teams.The salary range for this role is $188,000 - $258,500. Compensation for the role will depend on a number of factors, including a candidate's qualifications, skills, competencies, and experience. Pioneering Intelligence currently offers healthcare coverage, annual incentive program, retirement benefits and a broad range of other benefits. Compensation and benefits information is based on Pioneering Intelligence's good faith estimate as of the date of publication and may be modified in the future.Privacy 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