Senior Full-Stack Engineer

Understood•New York, NY

14h•Hybrid

About The Position

Understood is a nonprofit dedicated to shaping the world for difference by raising awareness of challenges and strengths of people who learn and think differently. They provide resources to help individuals navigate challenges, gain confidence, and find support and community so they can thrive. The organization operates with core values including continuous learning, intentional action, championing difference, inspiring change, and growing together. The Senior Full-Stack Engineer will report to an Engineering Manager and work across frontend, backend, and AI systems. This role involves joining a cross-functional team and collaborating closely with product, design, data, and content teams to build and evolve the platforms that power Understood.org and its AI-assisted experiences. The ideal candidate is comfortable working across the stack, from React and Next.js on the frontend to Python and Django on the backend, and brings demonstrated experience with LLM-powered products. You will contribute to a growing portfolio of AI tools, including conversational assistants and emerging multimodal experiences, while helping millions of families navigate learning and thinking differences. This is a hybrid role that requires a minimum of three (3) days a week in the NYC office, with a focus on Monday, Tuesday, and Thursday.

Requirements

7+ years of professional experience delivering production software, with meaningful depth in both frontend and backend development
Strong expertise in TypeScript, React, and Next.js, including experience building stateful, streaming interfaces
Demonstrated experience with Python and Django (or equivalent backend frameworks)
Proficiency in designing and building RESTful API’s
Experience working with relational databases (PostgreSQL, MySQL) and vector databases (Pinecone)
Comfortable working in the cloud (GCP, AWS, or similar)
Experience monitoring and instrumenting production services; we use Datadog and expect engineers to own their services’ health
Demonstrated ability leading projects as a technical lead
Ability to break complex projects into small, shippable increments and get them in front of real users quickly, using feature flags, staged rollouts, and experimentation platforms (Statsig or similar) to de-risk along the way.
Genuine interest in user problems. You read the support inbox, watch session replays, and treat "is this actually working for people?" as part of the definition of done.
Excellent communication skills, particularly when explaining technical matters to non-technical stakeholders and more junior engineers
Thrives in a collaborative environment and is motivated to promote a culture of teamwork, knowledge sharing, and continuous improvement
Familiarity with observability tooling beyond basic monitoring (distributed tracing, log analytics)

Nice To Haves

Production experience with LLM orchestration and agent design: LangChain / LangGraph / LangSmith or equivalents, multi-agent routing, memory and personalization layers (LangMem or similar), and Model Context Protocol (MCP).
A practical approach to making LLMs reliable in production: prompt engineering and tuning, systematic evaluation of outputs, guardrails and fallbacks, and designing around hallucinations and other failure modes.
Experience with retrieval-augmented generation (RAG) and vector databases (Pinecone, Weaviate, pgvector, or similar).
Experience building real-time, multimodal AI experiences (streaming text, voice, TTS/STT, Web Audio, WebRTC, real-time OpenAI SDKs), including optimizing latency and time-to-first-token (TTFT) in production.
Experience building or contributing to trust and safety systems (content moderation, input/output filtering, guardrails for AI-generated content)
Familiarity with privacy-by-design principles, data classification, and consent management in user-facing products
Understanding of compliance frameworks relevant to health-adjacent or child-focused digital products (e.g., COPPA, state companion-app laws, SOC 2, ISO 42001)
Experience with Contentful
Experience with asynchronous programming and task queues
Experience with Docker and/or Kubernetes
Proven ability to collaborate with and integrate code from external development agencies or contractors
Experience with React Native or mobile app development
A background in the nonprofit sector or a strong passion for using technology for social good

Responsibilities

Collaborate with cross-functional teams (product, design, data, content) to design, develop, and maintain features across the full stack
Build high-quality, accessible frontend experiences in Next.js, React, and TypeScript, including the stateful, streaming chat and multimodal (voice, text-to-speech, speech-to-text) interfaces that power our AI assistants.
Architect and ship the backend services and APIs (Python, Django, SQL) behind them, including integrations with PostgreSQL, Redis, Pinecone, and Contentful.
Monitor and improve AI performance KPIs, including system latency and time-to-first-token (TTFT)
Build accessible and localized products
Own your work across the entire software development lifecycle, from architecture and planning through development, deployment, and monitoring
Ship early and often. Break big problems into small, releasable increments and get them in front of users using feature flags, A/B tests, and progressive rollouts rather than big-bang launches.
Stay close to the people we serve. Dig into user feedback, support tickets, and product analytics to find the real problem, then ship the smallest change that solves it.
Leverage tools such as DataDog, Sentry, and Langsmith for monitoring, alerting, and analytics to proactively identify and resolve issues; own your services’ health
Collaborate effectively with both internal teams and external development partners to co-design solutions, troubleshoot integrations, and review code
Participate in code reviews, mentor junior engineers, and contribute to continuously improving development processes and best practices
Stay current with emerging technologies and industry trends, advocating for tools and practices that enhance our development process and product offerings