Senior Fullstack Engineer

About ExistenceExistence is a Time Intelligence platform on a mission to help people turn time into transformation. Built on the philosophy that quality of time equals quality of life, we enable users to fully account for all dimensions of their time, uncover hidden patterns in their energy and habits, and turn that data into actionable insights that drive meaningful life improvements. Through our intuitive cross-platform app, users track not just where their time goes, but how it makes them feel: connecting activities, reflections, and quality ratings to reveal what truly drives happiness, energy, and growth.The RoleWe're seeking a Senior Fullstack Engineer to join our small, collaborative team and help build the future of Time Intelligence. You'll work closely with designers, product managers, and fellow engineers across our entire technology stack, from our cross-platform app (web and mobile) to our backend APIs, delivering features that help people transform how they understand and experience their time. You'll work on both user-facing product features and internal admin tooling to help our team manage and support the platform effectively.We use modern technologies, including Flutter for cross-platform development, a Node.js backend with TypeScript, SQL databases, and cloud infrastructure. We emphasize clean architecture, comprehensive testing, and API-first design.Key ResponsibilitiesDesign and implement features across the full stack - from user interfaces to backend APIsCreate intuitive user interfaces for web and mobile platformsDevelop and maintain scalable REST APIs with proper authentication and authorizationBuild and maintain internal admin tooling for user management, data operations, support workflows, and platform monitoringWrite clean, maintainable, well-tested codeDesign and manage database schemas and migrationsImplement comprehensive testing strategies across all layersParticipate in API design and documentationOptimize application performance and user experienceCollaborate cross-functionally with designers, product managers, and engineers to deliver cohesive featuresParticipate in architecture decisions and technical directionReview code and mentor team membersDebug production issues and implement monitoring solutionsRequired QualificationsTechnical Skills:5+ years of professional software development experienceStrong proficiency in TypeScript/JavaScript or similar strongly-typed languagesProduction experience with backend web frameworks and RESTful API developmentExperience with SQL databases and ORMsUnderstanding of authentication/authorization patternsExperience building internal tools, admin panels, or back-office systemsSolid understanding of software engineering best practices and design patternsPreferred Skills:Cross-platform or mobile development experience (we use Flutter)Experience with cloud infrastructure (AWS, GCP, Azure)Familiarity with infrastructure as codeBackground in time tracking, productivity, or personal analytics productsExperience with app store deployment processesUnderstanding of data visualization and reportingExperience with caching strategies and performance optimizationSoft Skills:Strong problem-solving and debugging abilitiesExcellent written and verbal communicationAbility to collaborate effectively with designers, product managers, and engineers in a small team environmentSelf-motivated and able to work independentlyReceptive to feedback and eager to learn from othersUnderstanding of operational needs and user support workflowsWhat We OfferFull-stack ownership and technical influenceDirect impact on both user-facing features and internal operationsModern tech stack with continuous improvementsRemote-friendly work environmentSolid benefits for a startup (health insurance, non-matching 401K, 3 weeks PTO)How to ApplyPlease include:Your resume/CVLinks to your GitHub profile or portfolioBrief description of your most relevant project experienceExamples of internal tools or admin interfaces you've built (if available)