Kevin M.

Need a full stack developer who ships production-grade software and thinks like a CTO? I'm Kevin, a design engineer and founder of Tempo (Y Combinator). From early-stage startups to large companies, I build web and mobile apps in any framework, with a daily output guarantee so you see real progress every day. The guarantee is simple. You see shipped work every day, and we agree in writing on what lands each week. If I miss a week of agreed output, you don't pay for that week. That's how a fractional CTO should carry risk: on my side of the table, not yours. It also makes me a strong fit when you need someone to fix and finish AI-built apps that stalled with another developer. ✅ WHAT I BUILD • SaaS product development: production-grade apps. An MVP can be phase one, but it ships with auth, Stripe billing, tests, and an architecture that scales. • React Native app development: iOS and Android apps that share code and design with your web product. • AI app development and AI agent development: LLM features, agent workflows, and internal tools. • Fix and finish AI-built apps: Lovable, Bolt, and any other vibe-coded solution, or code left by a previous developer, cleaned up and taken to production. • Codebase audit and code review from a fractional CTO: a plain-English read on what to keep, what to rebuild, and what it will cost. • Custom web app development and custom dashboard development for ops, finance, and customer teams. • Auth, databases, payments, subscriptions, and third-party API integrations. ✅ WHY FOUNDERS TRUST THE WORK • I co-founded Tempo, backed by Y Combinator, Sequoia, and Golden Ventures. Our software has 200,000 users, and teams at 11x and Measure have used it. • Through Tempo's Agent+ program, I've worked with hundreds of companies on custom web app development and new features for existing software, including Dialogue (later acquired by Sun Life), Chorus AI, Molg, Keye, and Dakota. • I'm a senior full stack developer and design engineer with over a decade of hands-on engineering. • Before Tempo, I was Head of Product and part of the founding team at Perpetua, acquired by Ascential for about $150M. I wrote the algorithms behind its ad optimization engine. • Forbes 30 Under 30 (2024). Engineering degree from the University of Waterloo. "Tempo cut our development costs in half and increased our velocity by 3x." Aaron Myran, Cofounder, Chorus AI ✅ HOW I BUILD IT As your fractional CTO, I set the architecture, scope, and priorities, then build with Tempo's own AI agents and human reviewers, so you get senior output without a senior-team bill. Every release passes code review, automated tests, and visual regression checks before your users see it. As a design engineer, I also give your product a React design system your team can reuse instead of one-off screens. 1. A 20-minute call to pin down the product, stack, and deadline, whether it's AI agent development or a new SaaS product. 2. A phased plan with fixed-price milestones and a weekly feature target, whether you need one Next.js developer for a feature or a full product build. 3. Weekly demos on a staging link. 4. You own the code and IP from the first commit. Stack: React, React Native, Next.js, TypeScript, JavaScript, Tailwind, Node.js, Fastify, PostgreSQL, Supabase, Prisma, Stripe, Firebase, Vercel, AWS, OpenAI and Anthropic APIs, Storybook, Playwright. Flutter when a project calls for it. ✅ WHY THIS MODEL WORKS Most developers bill hours. I commit to output. Building with Tempo's AI agents means faster weeks and a lower bill than a typical agency. For a founder, that means a full stack developer with a fixed weekly target instead of an open-ended invoice, whether the work is SaaS product development or a single feature. ✅ WHO THIS IS FOR • Non-technical founders who need a fractional CTO and a production-grade build without hiring in-house. • Funded startups and small businesses with a thin engineering bench and a real deadline. • Teams with a half-built product that need someone to fix and finish AI-built apps or a stalled codebase. • Ops and finance teams that need custom dashboard development on top of their existing data. ✅ TWO WAYS TO START • Agent+: a monthly build engagement for SaaS product development, from first release to scale, backed by the daily output guarantee. • Hire a Human: a smaller monthly plan with 10 hours of senior full stack developer time, used whenever you need it. Send me what you're building, your stack, and your deadline, whether you need one React developer for a feature or OpenAI API integration across your product. We'll book a short call and map the fastest path to a production launch. Have a codebase in progress? Ask for a sample code review.