Senior Software Engineer II

WHO WE ARE Halcyon Labs is a nonprofit organization dedicated to creating cutting-edge technology that fuels Democratic victories and enables progressive causes to thrive. Our vision is simple: building change through the power of people. Since our founding, we’ve been building innovative solutions to revolutionize grassroots fundraising – if you’ve donated to a Democratic campaign or a progressive organization online, you’ve probably used our platform! We believe in putting power in the hands of small-dollar donors by helping thousands of groups — from local candidates to national movements — mobilize their communities and create a lasting impact. Every member of our team is deeply committed to advancing our shared mission and core values. Together, we are shaping the future of democracy. THE OPPORTUNITY As a Senior Software Engineer II on the AAA (Authentication, Authorization, and Access) team, you will be a senior technical contributor on one of Halcyon Labs's most critical teams spanning Product Engineering and Platform. AAA secures the front door for everyone who powers progressive fundraising — we make sure the right people get in, the wrong ones don't, and the ecosystem never has to choose between moving fast and staying safe. You'll own implementation and architecture decisions across identity, authentication, authorization, and access — work that every other product at Halcyon Labs depends on. You'll work full-stack across our Ruby and TypeScript codebases to establish technical foundations that enable secure, scalable, and reliable access for donors, campaigns, organizations, and Halcyon Labs employees. You will work in concert with product, data, platform, ops, and security teams to identify and execute high-impact improvements that unlock new product opportunities and ensure the reliability, predictability, and scalability of our platform. Our engineering and product organization is made up of empathetic and passionate people, organized into cross-functional teams that operate independently in alignment with broader organizational goals. WHAT YOU WILL DO Lead the technical execution of large, cross-team initiatives — including unifying login across Halcyon Labs products and shifting to role-based, least-privilege access controls at scale — contributing to architecture decisions and ensuring stability throughout. Work with your team to architect, refactor, and improve identity and access systems serving donors, campaigns, organizations, and internal users, breaking down work across epics and contributing technical expertise to shape roadmap prioritization. Partner with designers and product managers to shape the team's roadmap, anticipating stakeholder information needs and proactively raising potential competing product interests. Serve as a go-to resource for engineers across teams on architectural decisions, system design, and best practices — particularly in security, identity, and access control. Develop and champion best practices and design patterns to improve the maintainability and security posture of the platform. Demonstrate technical leadership through documentation, effective testing and monitoring, and clear, audience-oriented communication. Proactively share your knowledge and expertise with your teammates, fostering a culture of feedback and professional growth. Create spaces for individuals to be engaged, valued, and heard, setting cultural expectations around inclusivity within the team. Keep growing your craft. Seek out and act on feedback, learn from engineers across the org, and deepen your expertise, with your manager and teammates supporting you along the way. WHAT YOU BRING 5-8+ years of relevant professional experience, with a track record of leading complex technical initiatives from conception through delivery: multiple engineers, ambiguous requirements, real stakes. Experience designing simple, maintainable solutions to complex problems using well-accepted design patterns informed by industry experience. A strong understanding of performance, scalability, and security best practices, with the ability to recommend improvements; familiarity with OAuth/OIDC/JWT authentication patterns is a plus. Experience serving as a technical consultant and trusted resource for engineers seeking guidance on architecture, system design, and complex debugging. Ability to communicate effectively with non-technical stakeholders and to collaboratively translate business requirements and strategic goals into technical solutions, adapting your communication style to the audience. A track record of working closely with product and design to iterate on and refine requirements, with the ability to break down initiative-level work and contribute to roadmap prioritization. A growth mindset and real curiosity. You seek out feedback and act on it, stay open to being wrong, and treat experience as a foundation for learning more rather than a reason to stop. Comfort with or curiosity about AI coding assistants (such as Claud