Ben Tossell Builds a Custom AI-Powered Email App

Ben Tossell, creator of Ben's Bites, built a custom email client using AI coding agents. Dissatisfied with Gmail and Superhuman's feature bloat and cost, he wanted a split inbox with rules. Starting with Codex for the initial build, he switched to Factory for UI polish, using models like Opus and GPT-5.5. The app features split inboxes, keyboard shortcuts, command palette, reply/compose with 20-second undo send, one-click unsubscribe, search, rules, and filter sync. It uses the Google Workspace CLI for authentication and email operations. Performance issues were resolved by caching and optimistic UI updates. Email rendering was challenging, handling plain text, HTML, newsletters, and signatures; he reverse-engineered Obsidian's web clipper for inspiration. The app is designed to be agent-friendly with hidden selectors and debug endpoints. Tossell emphasizes learning by building, switching tools, and using agents to test via browser. His daily stack includes Pi with GPT-5.5 for brainstorming, Codex for coding, Factory for serious projects, Vercel/Stripe/Supabase for full-stack, and tools like here.now for quick sites and Clearly for documents.