Senior Software Engineer - Full Stack

About PreludePrelude is the only R&D platform built exclusively for animal health and nutrition. Our mission is to accelerate the development of life-saving medicines, devices, and nutrition for animals through smarter technology and superior service. Study designs are becoming more complex every year, making research more daunting and labor-intensive for animal health R&D teams. Prelude's platform makes complex research easy with the industry's most flexible, user-friendly technology, purpose-built for animal health studies and automating 90%+ of data management work. DescriptionWe are seeking a seasoned, deeply technical Senior Software Engineer to join our engineering team. In this role you will collaborate closely with engineers, DevOps, architects, product managers, and QA to drive the design and delivery of high-impact features for Prelude's customers.This is an individual contributor role - we have a highly senior team and we want someone who wants to do the work, not manage it. You take deep ownership of the features you build, hold a high bar for code quality and reliability, and can navigate ambiguity to deliver well-architected solutions independently. This role is built for someone who is genuinely excellent in the full web development stack. You may spend a week fully immersed in Next.js owning a complex UI end-to-end, the next week architecting backend services, or driving both simultaneously.This role is hybrid (Tuesday-Thursday in office) and is based in Austin, Texas.ResponsibilitiesDesign and implement complex full-stack features across our Next.js frontend and Node.js/Express.js backendArchitect and build scalable, maintainable RESTful APIs and backend servicesOwn quality end-to-end - write comprehensive unit, integration, and end-to-end tests and set the standardUse AI coding tools (Claude, GitHub Copilot, Cursor, or similar) as a core part of your engineering workflow. Drive technical decisions and contribute meaningfully to architecture discussions with pragmatic, well-reasoned proposalsCollaborate closely with product and design to deliver complex features with precision and polishParticipate in code reviews and raise the bar for quality, security, and maintainability across the codebaseBuild software that runs in and interacts with services on AWS using ECS, Lambda, S3, API Gateway, and related servicesProactively identify systemic issues - performance bottlenecks, architectural weaknesses, technical debt - and drive resolutionRequirementsExperience: 6+ years of professional software development with a track record of delivering complex features independently in production SaaS environmentsFrontend (must be exceptional): Expert-level proficiency in Next.js and React - component architecture, state management, performance optimization, rendering strategies, and UI polish at scale.Backend (must be exceptional): Expert-level experience with Node.js and Express.js, building production-grade APIs and services at scale.Code: TypeScript fluency across both frontend and backendCloud: Significant hands-on AWS experience (ECS, Lambda, S3, API Gateway, CloudWatch, IAM, and more)Testing: An unwavering commitment to testing - you write unit and integration tests as a matter of courseAI Fluency: Deep fluency across all modalities of AI-assisted development - chat, inline code completion, and agentic workflows (e.g. Claude Code, Cursor Agents, GitHub Copilot). You know when to spin up an agent to tackle a complex multi-step task vs. when a quick prompt is enough.APIs: Deep understanding of RESTful API design, OAuth/JWT authentication, and security best practicesJudgment: Ability to operate independently, navigate ambiguity, make sound technical decisions, and ship without close supervisionCommunication: Excellent written and verbal communication; able to articulate technical tradeoffs to engineers and non-engineers alikePreferredMobile: React Native or Expo experience for building cross-platform mobile applications - preferred for this role (not required, but a meaningful differentiator)MongoDB expertise - schema design, aggregation pipelines, index strategy, and query optimizationExperience designing event-driven systems (SQS, SNS, EventBridge, or similar)Familiarity with Redis, Elasticsearch, DynamoDB, or other specialized data storesExperience in a regulated industry (life sciences, healthcare, fintech) - GxP or FDA familiarity is a plusPrior SaaS product experience in a startup or high-growth environment