Backend Department Lead (Node.js)

Join us as a Backend Department Lead and drive the technical direction and development of the backend platform behind one of the fastest-growing AI products in the US market. We are looking for a strong technical leader who combines deep expertise in high-load system architecture with hands-on engineering leadership and experience in building and developing high-performing backend teams. In this role, you will have real technical ownership of our AI Gateway, generative pipelines, and mission-critical backend services powering a product already used by more than 2 million people. About Us: Zeely is the agentic AI platform for creating, launching, and scaling paid ads. Simply put: we've made the best AI solutions and marketing tools available to small and medium businesses — tools that used to be reserved for big brands with expensive marketing teams. The next big step: a B2B solution for large marketing teams and enterprise clients — workflows, creative analytics, and full control over campaigns across the whole team. For companies where performance marketing already runs at scale and needs more efficiency and automation. A few numbers that speak for themselves: • 4 years on the market — a stable, profitable company backed by international investors; • 6× growth over the past year; • 2,000,000+ businesses already use Zeely; • #1 in its category in the US market; • 200+ specialists on the team; • Markets: US + worldwide. Your Key Responsibilities: • Lead the Backend Department and set the technical direction for a team of 15+ backend engineers; • Own backend architecture and drive key technical decisions around scalability, reliability, performance, and system design; • Lead the evolution of our AI Gateway — the core platform layer powering text, image, voice, avatar, and video generation across multiple AI models and providers; • Design and evolve AI orchestration pipelines, optimizing routing, fallback strategies, generation quality, latency, and cost; • Scale backend services and infrastructure to support growing product traffic and increasingly complex workloads; • Drive engineering excellence across code quality, architecture, security, observability, testing, and operational reliability; • Lead strategic backend and AI initiatives, including our proprietary RAG pipeline, MCP integrations, and AI agent capabilities; • Stay hands-on with architecture, design reviews, code reviews, troubleshooting, and technically complex initiatives; • Grow the backend team through mentoring, performance management, technical development, hiring, and strong engineering practices; • Collaborate closely with Frontend, Mobile, QA, AI Engineering, DevOps, and Product teams to translate business goals into scalable technical solutions; • Partner with the Principal Engineer on infrastructure strategy, capacity planning, reliability, and cost optimization. What We Are Looking For: • 7+ years of commercial backend development experience with Node.js; • 3+ years in a technical leadership role such as Backend Lead, Team Lead, or Engineering Lead; • Experience leading and developing backend engineers, including mentoring and performance management; • 3+ years of hands-on production experience with NestJS; • Strong system design skills and proven experience designing and evolving microservice and distributed architectures; • Experience building and scaling high-load production systems; • Deep expertise in PostgreSQL and Redis, including performance optimization, data modeling, and caching strategies; • Experience with ORMs such as Prisma and Drizzle; • Hands-on experience with AWS, including EKS, RDS, SQS, S3, CloudWatch, and OpenSearch; • Strong practical knowledge of Docker and containerized environments; • Strong understanding of reliability, observability, monitoring, incident management, and on-call practices; • Ability to balance architectural strategy with hands-on engineering and pragmatic delivery; • Upper-Intermediate English or higher. Nice To Have: • Active AWS Solutions Architect or Developer certification; • Experience with Terraform or other Infrastructure as Code tools; • Experience optimizing infrastructure and architecture for cost, latency, and performance at scale; • Payment systems integration experience; • Backend experience across both mobile applications and web products; • Experience with GCP and Cloudflare; • Experience hiring and scaling engineering teams in fast-growing product companies. AI Expertise We Value: • Commercial experience integrating AI APIs such as OpenAI, Anthropic, Google, or other model providers; • Experience designing multi-model orchestration systems, including routing, fallbacks, retries, rate limits, and cost/latency optimization; • Understanding of production challenges around AI workloads, including reliability, observability, and provider dependencies; • Experience with AI-assisted engineering and code review tools such as Claude Code, GitHub Copilot, Cursor, or similar; • Understanding of RAG, embeddings, vector search, MCP, and AI agents; • Hands-on production experience is a strong plus. Why it’s exciting to work with us: • Take technical ownership of the backend platform behind a rapidly scaling AI product; • Shape architecture and engineering standards across a strong backend organization; • Work on real production challenges around high-load systems, AI orchestration, distributed architecture, and infrastructure at scale; • Build with cutting-edge AI technologies and directly influence how they are integrated into the product; • Join a strong engineering team with significant autonomy and direct impact on product and technical decisions; • Remote-first approach: work from anywhere, with the option to visit our offices in Warsaw and Kyiv; • Regular performance reviews with transparent growth and compensation discussions. Recruitment process: Intro Call → Intro with COO & Co-founder → Test Task → Technical Interview → Final Interview → Reference Check → Offer. Send us your CV — we'd love to get to know you!