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.
Responsibilities
What will you be doing?
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Build and ship core product features end to end across the full stack — from backend infrastructure on Cloudflare Workers to the Svelte-based frontend
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Own entire areas of the product autonomously. Talk to users, identify what needs to be built, and drive it to completion with minimal direction
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Work on making the core cloud agent experience exceptionally good — improving backend performance, user funnels, and UX
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Help define the engineering bar, architecture decisions, and pace of the company as it scales from 2 to 10+ engineers
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Collaborate daily with the founder in-person, shipping fast and iterating based on real user feedback