Senior Full-Stack Engineer

SundaySky•New York, NY

1d•Remote

About The Position

SundaySky is seeking a Senior Full-Stack Engineer to join their team. This is a hands-on individual-contributor role responsible for designing, building, testing, and operating complex capabilities across the web application, backend services, data integrations, and video creation platform. The ideal candidate will take ownership of significant product capabilities from technical discovery through production deployment, combining strong frontend and backend expertise with sound architectural judgment, product thinking, and the ability to elevate the technical performance of the broader team. This role requires the ability to work from product requirements and design concepts, identify technical gaps and edge cases, propose an implementation approach, and deliver production-quality software with limited oversight. The engineer will be involved in all aspects of the software development lifecycle, including design, implementation, testing, deployment, and production support, while also mentoring mid-level engineers and contributing to architectural standards.

Requirements

7+ years of professional software development experience, including substantial experience building production SaaS applications.
Strong full-stack development experience with modern JavaScript and TypeScript.
Advanced experience with a modern frontend framework, preferably React.
Strong knowledge of component architecture, state management, frontend performance, responsive design, and browser behavior.
Experience building complex, workflow-oriented web applications rather than primarily content-oriented websites.
Strong backend development experience using Node.js, Python, Java, C#, or a comparable server-side technology.
Experience designing and implementing REST APIs, event-driven services, background jobs, and asynchronous workflows.
Strong understanding of relational and non-relational data modeling.
Experience with PostgreSQL or another modern relational database.
Experience integrating with third-party APIs, authentication providers, data platforms, or enterprise systems.
Strong understanding of cloud-native application development, preferably within AWS.
Experience with containers, CI/CD pipelines, infrastructure environments, and modern deployment practices.
Strong understanding of automated testing strategies at the unit, integration, API, component, and end-to-end levels.
Experience diagnosing distributed application issues using logs, metrics, traces, database analysis, and browser tooling.
Working knowledge of application security, authorization, identity, secrets management, data protection, and secure coding practices.
Experience working with Git-based development workflows, pull requests, code reviews, branching strategies, and automated quality checks.
Strong understanding of software design principles, modular architecture, scalability, technical debt management, and maintainability.

Nice To Haves

Experience with video, audio, media processing, creative tooling, animation, rendering, or digital asset management.
Experience with browser-based motion graphics using React, JavaScript, CSS animations, Canvas, WebGL, or related technologies.
Experience with AI platforms, large language models, retrieval-augmented generation, prompt orchestration, or AI-generated media.
Experience building configurable enterprise platforms with permissions, approval workflows, auditability, and governance controls.
Experience with message queues, event buses, serverless services, or distributed job-processing systems.
Experience with infrastructure as code and production observability platforms.
Experience in a multi-tenant SaaS environment.
Experience improving or modernizing an established software platform while continuing to deliver new product capabilities.

Responsibilities

Design and implement end-to-end product capabilities spanning frontend applications, backend services, APIs, databases, and third-party integrations.
Translate product requirements, UX designs, and acceptance criteria into scalable technical solutions.
Lead the technical design of moderately complex and complex initiatives.
Break large capabilities into executable technical components and development increments.
Develop responsive, accessible, and maintainable user interfaces using modern JavaScript and TypeScript frameworks.
Design and implement backend services, application APIs, business logic, data models, and asynchronous workflows.
Build and maintain integrations with enterprise platforms, data sources, AI services, media providers, and other third-party systems.
Contribute to video creation, rendering, personalization, animation, asset management, analytics, and distribution capabilities.
Identify performance, scalability, reliability, security, and maintainability concerns before they become production issues.
Write automated unit, integration, component, and end-to-end tests.
Participate in code reviews and establish strong patterns for code quality and engineering consistency.
Diagnose and resolve complex production issues across application and infrastructure layers.
Improve observability through structured logging, monitoring, metrics, tracing, and actionable alerts.
Partner closely with Product, UX, QA, DevOps, and other engineers throughout the delivery lifecycle.
Mentor mid-level engineers through technical guidance, code reviews, pairing, and constructive feedback.
Contribute to architectural standards, engineering practices, shared components, and reusable platform capabilities.
Use AI-assisted engineering tools responsibly to accelerate development, testing, documentation, troubleshooting, and code modernization.
Participate in release readiness, production support, incident response, and root-cause analysis.