Developer Experience Engineer

We’re on a mission to make conversational AI agents think and respond at the speed of human conversation, everywhere they run. Today’s retrieval stack wasn’t built for real-time reasoning, so we’re building Moss: the real-time semantic search layer for the conversational AI. Backed by YC, we’re making every AI product feel instantaneous, deeply personalized, and actually useful in the real world.

We’re looking for a world-class Developer Experience Engineer to define and own how developers and AI agents interact with Moss. Your job is to make Moss feel obvious, fast, and delightful to use. From SDK design and API ergonomics to docs, examples, error messages, and onboarding flows - you will obsessively drive down the time it takes a developer to go from "What is this?" to "Holy sh*t, this is fast."

You’ll work directly with the founders and core engineering team to shape Moss’s public surface area: SDKs, APIs, examples, tooling, docs, and agent-friendly interfaces. This is not a DevRel or content-only role. You will ship code and own real systems.

What You’ll Do

• Own and continuously improve the end-to-end developer experience across Moss.
• Design developer-first (and agent-friendly) interfaces for real-time retrieval and agent workflows.
• Build and maintain sample apps, templates, and reference implementations for common AI use cases (RAG, voice agents, copilots).
• Obsess over time-to-first-query, time-to-aha, and activation metrics; and directly ship improvements.
• Work closely with users, design partners, and the internal backend team to turn real-world friction into product changes.
• Improve docs, guides, and error messages so developers rarely need to ask for help.
• Act as the internal voice of the developer: pushing back on confusing APIs, leaky abstractions, or DX regressions.
• Help shape Moss’s emerging Agentic Experience (AX) by designing interfaces that AI agents can consume reliably, not just humans.

Must-Have Requirements

• 5 years building and shipping production software in developer-facing products.
• Strong engineering background - you are comfortable diving deep into real systems, not just wrappers.
• Excellent proficiency in TypeScript and/or Python.
• Strong intuition for API design, naming, defaults, and ergonomics.
• Proven track record of improving developer workflows, SDKs, or tooling.
• Deep empathy for developers and a strong product sense.
• Bias for action, ownership mindset, and comfort operating in ambiguity.

Nice-to-Have Skills

• Proven track record of working at developer-first companies (e.g., Vercel, Supabase, Fly.io, Stripe, AWS, GCP).
• Familiarity with AI / LLM tooling, RAG pipelines, or agent frameworks.
• Exposure to Rust, WASM, or performance-sensitive systems.
• Experience building CLIs, SDK generators, or internal tooling.
• Open-source contributions or public technical writing.
• Founder or early-stage startup experience.

Why Join Moss

• DX is mission-critical here. This role directly shapes our product and growth.
• Build at the frontier of real-time AI infrastructure and agentic systems.
• Work directly with founders in a small, fast-moving, high-ownership team.
• Help define how developers build the next generation of conversational AI.
• Strong engineering culture with a high bar for quality and speed.
• Competitive compensation ($120K-$240K) and meaningful equity.