Founding Engineer

Rainbrand is the brand layer for agents. It turns a brand's identity, guidance, and assets into shared context that agents and products can use. That context evolves with the brand, alongside the tools where it is created and managed. We're a three-person team in YC, backed by Guillermo Rauch and Nebular VC. More than 500,000 assets have been generated with Rainbrand.

We're looking for an engineering generalist with depth in backend and AI systems. You'll help decide what to build, shape the architecture, and own what you ship in production. The immediate work centers on agents, data, and infrastructure, with room to follow a problem wherever it leads across engineering. Visa support is available.

What you'll work on

• Agents: Build agents, tools, memory, and workflows that create, maintain, and apply brand systems.
• Multimodal data: Build ingestion and source-understanding systems for websites, social media, and files, working across text and visual material.
• Storage and retrieval: Develop the data models, indexing, search, and retrieval that make brand context useful over time.
• AI quality: Build evaluations and feedback loops that help us understand quality, investigate failures, and improve our systems.
• Developer interfaces: Make Rainbrand useful to other products and agents through our API and MCP.
• Production infrastructure: Improve security, latency, and reliability. Build frontend surfaces and internal tools when they help solve the problem.

You'll make decisions about what we build now, what we simplify, and what can wait.

What we're looking for

• Strong fundamentals and production depth. You've built and operated backend and AI systems that people depend on, and can explain what you personally designed, why, what broke, and how you fixed it.
• You understand how the parts of a system fit together, reduce scope and complexity, and build primitives that remain useful as the product grows. You can ship a small, correct first version without losing sight of what it needs to become.
• Product and customer judgment. You understand who or what will use what you build, question whether it solves the right problem, and are comfortable talking directly with customers.
• AI tools are a substantial part of how you build, and you still understand the code, scrutinize the result, and take responsibility for its correctness and maintainability.
• You question requirements, explain your reasoning, defend decisions, and change your mind when the evidence is better.
• Urgency and follow-through: you make progress through ambiguity, surface problems early, and stay with difficult work through production.
• Low ego and high integrity.
• Care for craft and taste, and curiosity about how software can preserve the decisions that make a brand distinct.

Especially relevant experience

• Early-stage startup or founding-team experience, with meaningful responsibility for the systems you shipped.
• Open-source contributions, personal projects, or public technical work that shows curiosity and depth.
• Thoughtful engagement with developments in AI and engineering (GitHub, X, a blog, or elsewhere).
• Building agents, brand or creative tools, or multimedia and multimodal systems.
• Document intelligence, data processing, crawling, indexing, search, retrieval, or developer infrastructure.

Why join Rainbrand

Software can be called, composed, updated, and used at scale. We think brand should work that way too. Our ambition is to become critical infrastructure for agent-driven branding, marketing, and design. You'll build on the product and momentum we already have, with a direct hand in our architecture, what we build next, and the engineering culture around it.