Founding Software Engineer

About Companies Library Partners Resources Startup Jobs Log in Apply Sparkles Make everyone on your team an engineer Founding Product Engineer $150K - $200K • 0.50% - 1.00% • San Francisco, CA, US Job type Full-time Role Engineering, Full stack Experience Any (new grads ok) Visa Will sponsor Skills TypeScript Connect directly with founders of the best YC-funded startups. Apply to role › Ai Daniil Bekirov Founder About the role We’re hiring a founding engineer who moves fast, cares about craft, and wants real ownership from day one. You’ll live in a hacker house with the team and build side by side with the founders from day one. You should already use AI tools by default — pushing Cursor, Claude Code, Codex, and agent workflows hard, judging output critically, and moving faster without lowering the bar. What you’ll own Build and ship core product features end to end. Talk to users constantly, find bottlenecks, and ship fixes fast. Suggest new features, new products, and new internal tooling. Help set the engineering bar, architecture, and pace of the company. This is not a role where you can coast. It requires deep ownership, agency and responsibility. What we’re looking for Strong TypeScript and React skills. Roughly 1–5 years shipping real product software is a good baseline, but we will flex for someone unusually strong. Ability to build full-stack product features with high autonomy. Strong product instincts and a bias toward outcomes. High agency: you notice problems, propose solutions, and drive things to completion. Good design taste. You can make sensible UI/product decisions, and Figma fluency is a plus. Clear communication and strong judgment. Comfort with ambiguity and a founder-speed environment. Heavy AI-tool usage as part of your real workflow, not as a novelty. Strong pluses Experience with Cloudflare Workers, Durable Objects, service bindings, realtime systems, or collaborative/live product surfaces. Experience with building devtools Experience building sandboxed or safety-sensitive systems. Experience at a strong startup or fast product company. Two ways you might fit this role Lane 1: Experienced builder You’ve already spent a few years shipping product at a strong startup or fast-moving company. You’re now looking for much more ownership, much more scope, and much more upside. Lane 2: Exceptional emerging builder You may have only 1–2 years of experience, or an unconventional background, but you’ve already built real things, move unusually fast, have strong taste, and show real evidence of ownership. We care much more about slope, output, and judgment than pedigree. About the interview Screening call Technical interview 2 day work trial with an offer within 24 hours About Sparkles Sparkles is building Lovable for large existing codebases. Everyone is using coding agents now, but many teams are still stuck relying on outsourced development agencies, and it can take weeks to turn an idea into something live in production. Sparkles is building the AI workflow for teams shipping changes to existing products. We’re making it possible for product, design, marketing, and ops teams to safely make real changes to production codebases through GitHub-native workflows, reviewable pull requests, and the right guardrails. Sparkles was founded by Dan, who dropped out of University College London and previously worked with the former CTO of Monzo at Iterate.com. We raised $3.5M, backed by Y Combinator, Moonfire Ventures, and angels from OpenAI, Anthropic, a16z, General Catalyst, Cloudflare, and others. Sparkles Founded: 2025 Batch: W26 Team Size: 1 Status: Active Location: San Francisco   Founders Ai Daniil Bekirov   Founder Similar Jobs Aravolta Senior Software Engineer Hub Founding Engineer AlgoTest Founding Full Stack Engineer Axle Product Engineer Athelas Senior Backend Engineer, RCM AI Roboflow Infrastructure Engineer Candid Health Software Engineer Vorticity Kernel Engineer — Scientific Computing (SPU) Emergent Staff Engineer Alguna Forward Deployed Engineer (FDE) Flick Senior/Staff Product Engine