Principal / Senior Software Engineer
- Location
- Cambridge, MA USA · On-site
- Job type
- Full-time
- Level
- Lead / Staff
- Experience
- 5+ years
- Listed
- 30 days ago
Skills & highlights for this role
- AWS (ECS, S3, Lambda)
- Python
- AWS CDK
- TypeScript
Also useful
- LLM development
- AWS Solutions Architect certification
- SaaS security best practices
The Role
We 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.
Key Responsibilities
- Lead the design and development of customer-facing features across the front-end and back-end application stack.
- Partner closely with product managers, designers, and researchers to translate customer needs and product strategy into well-designed, high-impact features.
- Own features throughout the full product development lifecycle, from discovery and technical design through implementation, release, measurement, and iteration.
- Manage the release process for new features, including rollout planning, feature flagging, monitoring, and coordination across engineering and product teams.
- Use product analytics, feature experiments, and customer feedback to evaluate feature performance and guide continued development.
- Design scalable system architecture for rapidly evolving, AI-enabled back-end components.
- Contribute to user interface and interaction design, bringing technical insight into product and design decisions.
- Improve application delivery practices by implementing continuous integration, continuous delivery, automated testing, and operational best practices.
- Leverage AWS cloud infrastructure to build scalable, reliable, and efficient applications and AI-powered services.
- Uphold high standards of data security, privacy, and compliance across all applications.
Additional information
Successful 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.
Qualifications
- 5+ years of experience in software development, with a strong focus on building applications.
- Extensive experience with AWS services (including ECS, S3, Lambda, etc) or a similar cloud services provider.
- Proficient in Python.
- Demonstrated ability to build scalable, efficient, and secure software applications.
- Motivated and team oriented, with an ability to thrive in a multidisciplinary environment.
- Excellent communication and collaboration abilities.
Preferred Qualifications
- Experience with LLM development.
- AWS Certifications, such as Solutions Architect Associate or Professional.
- Able to build applications using the AWS CDK and Typescript.
- Knowledge of security best practices for SaaS solutions.
The Company
Iris 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.
Iris 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.
About Flagship
Flagship 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.
At 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.
Recruitment & 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.
The 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.
Equal opportunity and legal notices
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.
Flagship 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.
From Flagship Pioneering's careers page, first listed on Rolev.ai on October 10, 2026. Rolev.ai is not the employer.
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Common questions
Where is the Principal / Senior Software Engineer job at Flagship Pioneering located?
This Principal / Senior Software Engineer position at Flagship Pioneering is located in Cambridge, MA USA (On-site). Always check Flagship Pioneering's application page for specific state eligibility or relocation policies.
What qualifications are required for Principal / Senior Software Engineer at Flagship Pioneering?
For the Principal / Senior Software Engineer role, Flagship Pioneering highlights 5+ years of relevant experience; experience with AWS (ECS, S3, Lambda), Python, AWS CDK, TypeScript. Rolev.ai can score your existing resume against these requirements and show any skill gaps before you apply.
How do I apply for the Principal / Senior Software Engineer position at Flagship Pioneering?
This listing links directly to Flagship Pioneering's Greenhouse application page. You can apply directly on Flagship Pioneering's site, or use Rolev.ai to check your resume fit, generate a zero-hallucination tailored resume and cover letter for this posting, and autofill the Greenhouse application form in 1 click with the Rolev.ai Chrome extension. You always review the form and press Submit yourself.