A Builder Replaced $60-a-Month Calendly With One Cloudflare Worker in Ten Days, and Published the Bug Count
Serge Bulaev documented replacing a three-seat Calendly subscription with punctual.sh, an MIT-licensed scheduler built in ten days on a single Cloudflare Worker: 162 commits, 30,658 lines of TypeScript, 737 test assertions, $0/month, with Google Calendar and Microsoft 365 sync, round-robin teams, webhooks, an embed widget and an MCP server so agents can book meetings. The honest part is the failure data: a two-model adversarial review found 15 candidate issues and 14 were real bugs the 737 passing tests never caught, because agent-written tests check what the agent believed it built. He also notes Cal.com's April 2026 relicense to cal.diy under MIT cut 411,000 lines including teams, workflows, insights and SSO, and is marked non-production.
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