feat(render): use experimental react-markup on react-server export

[gabrielmfern]

I was experimenting with next-intl and calling getTranslations fails in the preview server:

Error: `getTranslations` is not supported in Client Components.
    at <unknown> (emails/my-email-template.tsx:82803:11)
    at MyEmailTemplate (emails/my-email-template.tsx:82819:20)

Because we don't import from the react-server condition when bundling with esbuild for previewing.

But if we did, react-dom would also fail because the code exported through the react-server condition is

'use strict';

throw new Error(
  'react-dom/server is not supported in React Server Components.'
);

This is because react-dom is really not meant to run in a react-server environment, and that's also why we, to this day, still get errors when running in Next.js 15+ edge (see vercel/next.js#71865 (comment)).

For that reason, the React team started developing react-markup, which is still experimental. The only way for us to prefer react-server is if we use react-markup ourselves with the react-server condition for @react-email/render. Since this is experimental, and we're trying out solutions we can have this at least in canary.

The preview release from this PR also lets us play around

---

Summary by cubic

Add a react-server export for @react-email/render that uses experimental react-markup to render HTML in RSC environments. This fixes preview/Next.js RSC failures (e.g., next-intl getTranslations) by avoiding react-dom/server.

• New Features

  • New "react-server" export that renders via react-markup with Suspense.
  • Added conditional exports and build output for react-server to replace legacy server rendering in previews/Next RSC.
  • Supports plain text output and handles large emails without hydration markers and high-byte characters.

• Dependencies

  • Added react-markup 0.0.0-experimental-93fc5740-20251113.

^{Written for commit 4e64f10. Summary will update automatically on new commits.}

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[vercel]

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Project	Deployment	Preview	Comments	Updated (UTC)
react-email	Ready	Preview	Comment	Nov 14, 2025 0:58am
react-email-demo	Ready	Preview	Comment	Nov 14, 2025 0:58am

[pkg-pr-new]

Open in StackBlitz

npm i https://pkg.pr.new/resend/react-email/@react-email/render@2689

commit: 4e64f10