Katapult Labs

• Technical leadership and architecture (the heart of the role). You own the technical bar across web, backend, data, mobile, cloud, infrastructure, and security. You make the hard architecture calls, lead the reviews, and design the foundations of new projects. • Engineering org, culture, and talent. You grow our engineering organization the modern way: horizontal, high-trust, outcome-driven, not stacked with management layers. You set the hiring bar, define how we level builders, and shape the culture, incentives, and processes that make strong engineers want to do their best work here. • AI harness engineering as a core discipline. You treat the harness as real engineering: the scaffolding, tools, context, memory, evals, and guardrails that wrap a model and turn it into something production-grade. You set the judgment for where AI speeds us up and where it quietly drops the quality bar, and you coach the team to build at that level (the harness, not just the prompts). • Delivery and the strike team. When a new engagement needs the best of the best to stabilize it or set the right foundation, you're on the strike team. You roll up your sleeves on prototypes, early product builds, architecture, and the hard first 20%. Then you hand off clean to the squad that runs with it. • Partner and commercial partnership (grows with the role). You work directly with founders and C-level stakeholders, with the presence to represent Katapult at the highest level. When technical weight helps win or shape the right work, you step into the sales motion.

• Design, build, and maintain scalable ML, AI, and data-platform services that power production features end-to-end. • Operate LLM applications in production: chat with memory, retrieval, prompt management, versioning, and experimentation. • Build and run structured evaluation pipelines (golden datasets, regression checks) so changes ship with confidence. • Own AI/ML observability and monitoring instrument, trace, and debug model behavior in prod with tools like Langfuse or MLflow (knowing one is enough). • Integrate and serve LLM-agnostic model backends (e.g., Anthropic models via Bedrock and Vertex) and support deterministic/custom ML where open-source models fall short (e.g., document/PDF parsing). • Contribute to data lineage, governance, and compliance as the platform matures. • Partner closely with product and the broader team to move fast without breaking quality.

Founding Engineer Location Miami, Fl Employment Type Full time Location Type Remote Department Katapult Labs Department: Sunlight Job Description: Hybrid Role: 85% remote, but requires 3 nights on-site in Miami or NYC every month. This is NOT a remote position. Candidates must live in these locations, have valid work authorization, and be fully bilingual (English/Spanish). Please apply only if you meet these specific criteria. About the Company Our partner is a stealth-stage legal technology company applying AI to plaintiff-side litigation at institutional scale, with eyes toward reinventing the way law is practiced end-to-end. They operate at the intersection of special situations litigation and litigation finance building infrastructure that doesn't yet exist in the legal industry. They raised a seed round that was 75% oversubscribed in February 2026, and they're building the team that will define how this company grows. Their engineering culture is small, deliberate, and high-stakes. This isn't a place where you hand off tickets and wait for feedback. It's a place where precision matters, where the domain has real consequences, and where the expectation is that you think in systems, not features. The Role We're looking for a Founding Builder Engineer; the next person to join the core team. This isn't a job description for an engineer slot. It's an invitation for someone who has already proven they belong in the top 1% of their craft and wants to build something that matters. You'll work across the full stack — backend-first, owning architecture end-to-end, and with taste for elegant and convenient UX/UI while collaborating closely with a product-leaning counterpart. You'll design systems around AI, not just use it. LLM orchestration, agentic workflows, MCP integrations. The domain is regulated and high-precision. Prior exposure to legal tech, compliance-adjacent data pipelines, or enterprise SaaS in a domain with real stakes is a strong signal. You understand why a wrong output has consequences and you build accordingly. What We're Looking For You have Software engineering depth with a backend-first instinct. You're comfortable owning complex platforms and products end-to-end without hand-holding, and you've shipped production-grade systems that you'd stand behind today. You're AI-native by default. You design systems with and for AI, not around it. You've built with LLMs in production not as a feature, but as infrastructure. You operate at high autonomy, low maintenance, low ego. You communicate precisely, flag blockers early, ship in fast-moving environments, and don't need structure imposed from above. You've worked in a domain where precision matters: legal, compliance, healthcare, fintech. You know what it means to be wrong in a regulated context. Tech Stack - Frontend: Next.js 16, React 19, TypeScript 5.9, Tailwind CSS 4, shadcn/ui, Radix UI, Recharts, MapLibre GL, Framer Motion, Lucide React - AI: Anthropic Claude API (SDK), Server-Sent Events streaming, custom agentic tool system, dynamic skill loading from S3 - Backend: Next.js API routes, Auth.js (NextAuth v5), Drizzle ORM, PostgreSQL, DuckDB, S3-backed Parquet files - Data Pipeline: Python 3.13, Hive-partitioned Parquet on S3, DuckDB analytical engine Logistics - Based in New York or Miami preferred; exceptional candidates in other locations considered - Person fluent in English and Spanish - 85% remote with monthly in-person meetings in New York and Miami (3 nights) - Monster equity: 0.20%–0.99% of the business as of May 2026 — meaningful, early-stage ownership in a well-funded company - 4-round interview process: founder screen (25 min) → blind work sample → half-day panel (ethics + adversarial assessments) → social event with the team - Founding Builder — New York / Miami

• Build a high quality, native first iOS experience for a premium investment platform. • Craft pixel perfect UI and smooth, thoughtful interactions across the app. • Ship real features end-to-end, including authentication, transactions, and data flows. • Iterate quickly using modern AI coding tools and workflows. • Contribute across mobile and web when needed to support product velocity. • Collaborate closely with product and design to refine and elevate the user experience.

• Deeply understand the business model, user needs, and platform workflows to inform product decisions. • Design and iterate on low and high-fidelity prototypes to validate ideas before development. • Define, prioritize, and maintain the product backlog in alignment with business goals and user value. • Lead QA processes to ensure features are delivered with quality and meet acceptance criteria. • Act as a connector between engineering, design, and stakeholders pushing forward on all fronts. • Communicate progress, trade-offs, and blockers clearly with US-based founders and stakeholders in English.

• Work with an AI-first mindset, identifying opportunities to automate and simplify complex compliance and administrative processes. • Design and build end-to-end features across the platform (marketplace, applicant flows, compliance tooling, property management dashboard). • Develop clean, intuitive user interfaces for diverse user types (applicants, property managers, state entities). • Design and maintain backend services and APIs that support complex compliance workflows and data management. • Contribute to platform architecture decisions, ensuring scalability and reliability as the product grows. • Collaborate directly with US-based founders and stakeholders, communicating progress and trade-offs clearly in English. • Maintain high standards for code quality, testing, and documentation.