Founding Engineer

We are looking for a Founding Engineer with 1–5 years of experience to join Sparkles as the second engineering hire and help build the future of cloud-native AI coding agents. You'll work directly alongside a YC-backed solo founder on the literal frontier of agentic development — competing with Cursor, Claude Code, and the labs themselves. We need someone who is deeply AI-native, moves at founder speed, and thrives with full ownership over the product.

This is a ground-floor opportunity with meaningful equity at a company backed by $3.5M from Y Combinator, Moonfire Ventures, and angels from OpenAI, Anthropic, a16z, General Catalyst, and Cloudflare. What will you be doing? Build and ship core product features end to end across the full stack — from backend infrastructure on Cloudflare Workers to the Svelte-based frontend Own entire areas of the product autonomously.

Talk to users, identify what needs to be built, and drive it to completion with minimal direction Work on making the core cloud agent experience exceptionally good — improving backend performance, user funnels, and UX Help define the engineering bar, architecture decisions, and pace of the company as it scales from 2 to 10+ engineers Collaborate daily with the founder in-person, shipping fast and iterating based on real user feedback