Senior Founding Software Engineer
About the CompanyArbor is building infrastructure for AI-native experiences and emerging agent-driven surfaces. We believe the next generation of user interaction, discovery, and commerce will increasingly occur through AI-powered systems, and we're building the foundational technology to help power that future. As an early-stage company, we're looking for engineers who enjoy tackling ambitious technical challenges, building from first principles, and helping shape both the product and the company. We believe the early stages of building a company benefit from close collaboration and rapid iteration. Our team works primarily in person in the San Francisco Bay Area.About the RoleWe're looking for a Senior Founding Software Engineer to help build the core infrastructure, platforms, and systems that power Arbor's products and AI-native experiences. As one of the earliest engineers at Arbor, you'll work closely with the founders to define system architecture, design APIs and services, and build the foundational technology that powers emerging agent-driven experiences. You'll own major technical areas end-to-end, write high-quality production systems, and help shape the company's technical direction. This role spans backend infrastructure, platform architecture, experimentation, measurement, data systems, and real-time decisioning. You'll help build scalable systems that directly impact product performance, user experience, and business outcomes. Our primary languages today include Python, TypeScript, and Go, though we value strong engineering fundamentals and learning ability over experience with specific technologies.ResponsibilitiesDesign and build low-latency systems for real-time decisioning and servingOwn backend systems for targeting, pacing, allocation, and delivery infrastructureBuild large-scale measurement systems for attribution, reporting, experimentation, and analyticsDesign APIs, services, and platform capabilities that power AI-native products and agent-driven experiencesDrive platform architecture for scalability, performance, reliability, and operational excellenceImprove latency, throughput, correctness, observability, and developer productivity across systemsBuild and evolve data models, pipelines, and infrastructure that support intelligent applicationsCollaborate closely with founders to translate product and business goals into technical solutionsHelp establish engineering best practices, development workflows, and technical standards as the team growsContribute to hiring, technical reviews, and engineering culture as an early member of the teamQualificationsStrong foundation in computer science fundamentals, including data structures, algorithms, distributed systems, and system designDeep experience building backend systems, distributed systems, and production infrastructureProven track record of building and scaling production systems with meaningful business impactExperience designing and building APIs, services, and scalable cloud-based architecturesExperience with databases, distributed storage, messaging systems, and performance optimizationStrong software design, debugging, and production engineering skillsExperience owning and operating critical production systems, including architecture, implementation, reliability, monitoring, and performanceStrong system design skills and experience making architectural tradeoffs in production environmentsDemonstrated ability to independently own complex technical projects from design through production operationComfortable operating in ambiguous, fast-moving environments with high ownership and accountabilityStrong written and verbal communication skillsTypically 6+ years of professional experience designing, building, and scaling production software systemsRequired SkillsStrong foundation in computer science fundamentals, including data structures, algorithms, distributed systems, and system designDeep experience building backend systems, distributed systems, and production infrastructureProven track record of building and scaling production systems with meaningful business impactExperience designing and building APIs, services, and scalable cloud-based architecturesExperience with databases, distributed storage, messaging systems, and performance optimizationStrong software design, debugging, and production engineering skillsExperience owning and operating critical production systems, including architecture, implementation, reliability, monitoring, and performanceStrong system design skills and experience making architectural tradeoffs in production environmentsDemonstrated ability to independently own complex technical projects from design through production operationComfortable operating in ambiguous, fast-moving environments with high ownership and accountabilityStrong written and verbal communication skillsTypically 6+ years of experience designing, building, and scaling production software systemsPreferred SkillsExperience building monetization, advertising, marketplace, auction, ranking, recommendation, experimentation, attribution, or real-time decisioning systemsExperience building systems where performance, correctness, reliability, and business outcomes are tightly coupledExperience operating large-scale production systems with strict latency, availability, and throughput requirementsExperience with large-scale data infrastructure, analytics, experimentation, or measurement systemsExperience building AI-powered products, agent systems, retrieval systems, recommendation systems, or data-intensive applicationsExperience using AI-assisted development tools to improve engineering productivity and velocityExperience working in early-stage startups or building 0→1 products and platformsPay range and compensation packageBe among the first ~10 employees. Own critical systems with direct impact on the company's success. Work directly with founders on architecture, product direction, and technical strategy. Help shape the engineering culture and technical foundation of the company. Build systems at the intersection of AI, infrastructure, commerce, and emerging user experiences. Receive meaningful ownership through early-stage equity. #J-18808-Ljbffr