Source: https://seerepo.com/compare/calcom/cal.diy/vs/resend/react-email
Markdown source: https://seerepo.com/compare/calcom/cal.diy/vs/resend/react-email.md
Description: cal.diy and react-email share 14 technologies: Next.js, Redis, React, Zod, Tailwind CSS, classnames, sonner, Framer, Radix UI, Lucide, node-html-parser, tailwind-merge, entities, and marked. Both are written in TypeScript.

# cal.diy vs react-email

cal.diy and react-email share 14 technologies: Next.js, Redis, React, Zod, Tailwind CSS, classnames, sonner, Framer, Radix UI, Lucide, node-html-parser, tailwind-merge, entities, and marked. Both are written in TypeScript.

- [calcom/cal.diy](https://seerepo.com/r/calcom/cal.diy): Scheduling infrastructure for absolutely everyone.
- [resend/react-email](https://seerepo.com/r/resend/react-email): 💌 Build and send emails using React

## What they share and what sets them apart

- In common: Next.js, Redis, React, Zod, Tailwind CSS, classnames, sonner, Framer, Radix UI, Lucide, node-html-parser, tailwind-merge, entities, marked
- Only in cal.diy: connect, @nestjs/core, Postgres, @nestjs/bull, @nest-lab/throttler-storage-redis, bull, Google, Sentry, Stripe, NestJS, @next/third-parties, Vercel, PostHog, @trpc/server, tRPC, lru-cache, kysely, next-auth, helmet, class-validator, class-transformer, nest-winston, tslog, winston, winston-transport, next-themes, class-variance-authority, React Hook Form, TanStack, @formkit/auto-animate, react-select, react-inlinesvg, react-sticky-box, bcryptjs, jose, otplib, markdown-it, qrcode, react-qr-code, @hookform/resolvers, ink, ink-text-input, ink-select-input, ical.js, Base UI, nodemailer, handlebars, dompurify, jimp, remove-markdown, sanitize-html, sharp, turndown, Prisma, node-ical, lexical, react-easy-crop, cmdk, react-colorful, react-day-picker, @lexical/markdown
- Only in react-email: Resend, PostCSS, tiptap, react-three, three, prism-react-renderer, vaul, vercel, ora, @floating-ui/react-dom, hast-util-from-html, prismjs, prompts, picospinner, html-to-text, html5parser, @lottiefiles/dotlottie-react

## Side by side

| | cal.diy | react-email |
|---|---|---|
| Size | 554,567 lines written, 4,308 code files | 209,349 lines written, 931 code files |
| Who writes it | 6.3% of its commits signed by AI. With Devin, Claude Code, CodeRabbit, Cursor, and GitHub Copilot | 3.3% of its commits signed by AI. With Cursor, Claude Code, and GitHub Copilot |
| Activity | Last push November 3, 2026, 16,069 commits, 49,716 stars | Last push November 5, 2026, 2,625 commits, 19,913 stars |
| Tests | 644 test files. 14.8% of its code files have a test that imports them | 194 test files. 18.3% of its code files have a test that imports them |

- Size: Lines written by people and agents, without generated ones; code files, without tests.
- Who writes it: A commit counts as AI's when it carries its signature: a Co-Authored-By line, its author name or the merge of its branch.
- Activity: From GitHub and its history, on the day SeeRepo read it.
- Tests: The files that test the code, and the share of code files a test imports.

## Frequently asked questions

### Which is bigger, cal.diy or react-email?

cal.diy, with 554,567 lines written; react-email has 209,349.

The proof: [calcom/cal.diy's code at commit 2eb48ec](https://github.com/calcom/cal.diy/tree/2eb48eccd8aca8a0c0ffabf28cf92e298b33ecee)

### Which has more GitHub stars, cal.diy or react-email?

cal.diy, with 49,716 stars; react-email has 19,913.

The proof: [calcom/cal.diy on GitHub](https://github.com/calcom/cal.diy)

### Which has more tests, cal.diy or react-email?

cal.diy, with 644 test files; react-email has 194.

The proof: [calcom/cal.diy's code at commit 2eb48ec](https://github.com/calcom/cal.diy/tree/2eb48eccd8aca8a0c0ffabf28cf92e298b33ecee)

### Which was updated more recently, cal.diy or react-email?

react-email: its last push was on November 5, 2026, and cal.diy's on November 3, 2026.

The proof: [resend/react-email's commits on GitHub](https://github.com/resend/react-email/commits)

### Which has more commits signed by AI, cal.diy or react-email?

cal.diy: an AI signed 6.3% of its commits, with Devin, Claude Code, CodeRabbit, Cursor, and GitHub Copilot; in react-email, 3.3%.

The proof: [the commits each tool signed in calcom/cal.diy](https://seerepo.com/r/calcom/cal.diy/ai)

## Sources

- calcom/cal.diy: Read on November 5, 2026, at commit 2eb48ec (https://github.com/calcom/cal.diy/tree/2eb48eccd8aca8a0c0ffabf28cf92e298b33ecee)
- resend/react-email: Read on November 5, 2026, at commit d8a0778 (https://github.com/resend/react-email/tree/d8a077865793516917f42993a1e13becd797cad1)

## What is your repo built with?

Any public repo, with no account: https://seerepo.com/r/owner/repo/built, with the owner and name it has on GitHub.