fix(render): edge environment errors with MessageChannel

[gabrielmfern]

This is meant for partially fixing #1630 which is caused by a browser JS API trying to be used on the edge environment. React DOM does provide this react-dom/server.edge export that you can use which doesn't use that API, and works for raw edge environments, like Cloudflare Workers. I've tested this on our Cloudflare Workers Example

But, when running in Next.js on the edge, this error happens after this pull request:

(rsc)/./node_modules/@react-email/render/dist/edge-light/index.js
 ⨯ Error [TypeError]: Cannot set properties of undefined (setting 'recentlyCreatedOwnerStacks')
    at new Promise (<anonymous>)
    at Generator.next (<anonymous>)

And according to vercel/next.js#71865, this happens because we're running React DOM in a React Server environment which isn't really allowed. Not sure what we can do to actually circumvent this, except for waiting for https://github.com/facebook/react/tree/main/packages/react-markup to get into a stable version, or use the experimental itself.

[changeset-bot]

🦋 Changeset detected

Latest commit: 8549fa1

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 3 packages

Name	Type
@react-email/render	Patch
@react-email/components	Patch
playground	Patch

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Project	Deployment	Preview	Comments	Updated (UTC)
react-email	Ready	Preview	Comment	Aug 19, 2025 5:43pm
react-email-demo	Ready	Preview	Comment	Aug 19, 2025 5:43pm

[pkg-pr-new]

Open in StackBlitz

npm i https://pkg.pr.new/resend/react-email/@react-email/render@2225

commit: 8549fa1

[adrai]

Does this address also this issue? #1630

[gabrielmfern]

@adrai yes, but introduces another error for Next.js running on the edge

[lucasfcosta]

LGTM! I also tested this manually on CloudFlare and was able to repro both the error and the fix.

As I discussed with @gabrielmfern it seems that 1.1.0 of @react-email/render doesn't cause this, so one has to ensure it's resolving to 1.2.0 to be able to reproduce it.

Once reproduced, this PR's changeset fixes it (pnpm i https://pkg.pr.new/resend/react-email/@react-email/render@2225).