Senior Software Engineer I, Decision Systems

Company Description Etsy is the global marketplace for unique and creative goods. We build, power, and evolve the tools and technologies that connect millions of entrepreneurs with millions of buyers around the world. As an Etsy Inc. employee, whether a team member of Etsy or Depop, you will tackle unique, meaningful, and large-scale problems alongside passionate coworkers, all the while making a rewarding impact and Keeping Commerce Human. What’s the role? Decision Systems turns decisions and confidence signals into adaptive production systems that safely control exposure, payouts, and friction at scale. As a Senior Software Engineer on this team, you will: Lead projects aligned to your squad’s objectives in the Trust & Safety space. Design and build decisioning services and pipelines that combine rules, model outputs, and human feedback into high throughput, low-latency systems. Turn risk and enforcement strategies into concrete, observable controls that protect Etsy’s buyers, sellers, and business. Collaborate across Risk, Operations, and other engineering teams to build for the external users who experience the outcomes of these decisions. This is a full-time position reporting to the Engineering Manager, Decision Systems. In addition to salary, you will also be eligible for an equity package, an annual performance bonus, and our competitive benefits that support you and your family as part of your total rewards package at Etsy.  For this role, we are considering candidates based in the United States. Candidates living within commutable distance of Etsy’s Brooklyn Office Hub may be the first to be considered. For candidates within commutable distance, Etsy requires in-office attendance once or twice per week depending on your proximity to the office. Etsy offers different work modes to meet the variety of needs and preferences of our team. Learn more details about our  work modes and workplace safety policies here. What’s this team like at Etsy? Decision Systems sits within Etsy’s Detection & Enforcement vertical, partnering closely with ML Engineering and Operations teams to build and evolve the systems that enact decisions at scale. The team is: Purposeful, focused on protecting the marketplace while minimizing unnecessary friction for trustworthy buyers and sellers. Highly collaborative and cross-functional, building strong relationships with PMs, data scientists, analysts, and operations partners to align on risk strategies and enforcement behavior. Data-informed, using logs, metrics, and feedback from Ops to iterate on controls and improve decision quality over time. What does the day-to-day look like? As a Senior Engineer, your day-to-day involves a mix of technical leadership, hands-on implementation, and cross-functional collaboration focused on building robust and secure enforcement systems. Design and build decision systems: Implement and evolve services that evaluate signals, scores, and rules to produce consistent enforcement outcomes (e.g., holds, reviews, limitations). Collaborate across teams: Partner with Ops, Analytics, ML and Product to clarify requirements, align on tradeoffs, and share impact. Join partners in incident remediation as needed to identify patterns of abuse and shut them down. Mentor and elevate others: Mentor other engineers via pairing, code reviews, and sharing context. Help others break down problems and reason about risk tradeoffs. Of course, this is just a sample of the kinds of work this role will require! You should assume that your role will encompass other tasks, too, and that your job duties and responsibilities may change from time to time at Etsy's discretion, or otherwise applicable with local law. Qualities that will help you thrive in this role are: You have experience crafting and operating backend services that make or orchestrate automated decisions (for example, risk controls, rules engines, or workflow/decision systems), ideally in a large-scale, distributed environment. You are familiar with the world of cybersecurity, particularly financial fraud. You are proficient in at least one backend language such as PHP, a frontend language like Typescript, and a query language like SQL- and you’re comfortable learning the rest of our stack as needed. You use data, experimentation, and engineering principles to shape solutions, and you incorporate what you learn back into the system. You enjoy collaborating with a diverse set of partners, and you build trust through empathy and follow-through. You take ownership in ambiguous spaces, while bringing in the right collaborators and asking for guidance when it unblocks the work. You invest in tests, monitoring, and documentation. You use incidents and surprises as input to harden systems and improve craft. Additional Information   What's Next If you're interested in joining the team at Etsy, please share your resume with us and feel free to include a cover letter if you'd like. As we hope you've seen already, Etsy is a place that values individuality and variety. We don't want you to be like everyone else -- we want you to be like you! So tell us what you're all about.   Our Promise At Etsy, we believe that a diverse, equitable and inclusive workplace furthers relevance, resilience, and longevity. We encourage people from all backgrounds, ages, abilities, and experiences to apply. Etsy is proud to be an equal opportunity workplace. We 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, or any other characteristic protected by applicable law. If, due to a disability, you need an accommodation during any part of the application or interview process, please let your recruiter know. While Etsy supports visa sponsorship, sponsorship opportunities may be limited to certain roles and skills.