Katapult Labs - Staff Full-Stack Engineer

• This role calls for a senior backend engineer who takes full ownership of complex systems end to end. The ideal candidate builds with AI as a core part of the architecture, having shipped production systems using LLMs and media generation APIs, and knows when to use agentic approaches versus deterministic pipelines. They work autonomously, communicate clearly, surface blockers early, and thrive in fast moving environments without needing top down structure. Experience in a precision sensitive domain such as ad tech, fintech, or healthcare is essential, along with a proven track record building auditable, recoverable systems where mistakes carry real consequences. • Frontend: Next.js 15 (App Router), React 19, TypeScript 5.9, Tailwind CSS, Radix UI, TanStack Query/Table, Zustand, Framer Motion, Recharts, Lucide • Frontend: • Backend: Firebase Cloud Functions v2, Firebase Auth, Cloud Firestore, Cloud Storage, Cloud Run, Cloud Tasks, Cloud Scheduler, Google Cloud Secret Manager • Backend: • Data: Google BigQuery, Firestore, Pinecone (vector memory), Puppeteer based screenshot service • Data: • AI: Anthropic Claude (Agent SDK), OpenAI, Google Gemini, OpenRouter, fal.ai (image), Seedance 2.0 (UGC video), MCP server tooling • Integrations: Meta Marketing API, Snapchat Ads API, TikTok Business API, Apple Search Ads, AppsFlyer, Slack (Block Kit, LettaBot) • Integrations: • Quality: Vitest, Testing Library, Firebase Rules unit testing, Playwright style E2E, ESLint, Prettier • Quality: • Experience with Meta Marketing API, Snapchat Ads API, TikTok Business API, or Apple Search Ads • Background in ad tech, mar tech, or performance marketing engineering • BigQuery or analytics warehouse experience for performance data and learning loops • Familiarity with Slack apps, Block Kit, or workflow integration • Exposure to MCP, agent tooling, or AI workflow orchestration in production.