fix(ui): update existing Resend templates instead of creating duplicates

[tazwar9t62]

Summary

Fixes #3194.

The Resend integration in the preview server always created a new template on every upload. That made repeated uploads produce duplicate templates instead of updating the original one.

This PR changes the upload flow to behave like an upsert:

• use a deterministic Resend alias per template
• update an existing template when a match is found
• only create a new template when no existing template can be matched

Changes

• added a dedicated Resend template upsert helper in packages/preview-server/src/utils/resend-template-upsert.ts
• added focused tests for alias generation and matching behavior in packages/preview-server/src/utils/resend-template-upsert.spec.ts
• updated packages/preview-server/src/actions/export-single-template.ts to use the upsert flow instead of calling resend.templates.create() directly
• updated packages/preview-server/src/components/toolbar/resend.tsx so both single upload and bulk upload use the same normalized template identity
• updated the toolbar messaging so the UI distinguishes between template creation and template update

Why

Previously the preview server always called resend.templates.create(), so every upload created a new dashboard template.

This implementation introduces a stable alias for each template and uses it to find and update the same template on future uploads. It also includes a fallback for older templates created before aliases were used, including older single-upload names that included the file extension.

That keeps new uploads stable while still allowing existing templates to be migrated into the new flow.

Verification

Ran:

• pnpm --filter @react-email/preview-server exec vitest run src/utils/resend-template-upsert.spec.ts
• pnpm exec biome check packages/preview-server/src/utils/resend-template-upsert.ts packages/preview-server/src/utils/resend-template-upsert.spec.ts packages/preview-server/src/actions/export-single-template.ts packages/preview-server/src/components/toolbar/resend.tsx

Results:

• focused tests passed
• formatting and lint checks passed on touched files

Note:

• pnpm --filter @react-email/preview-server exec tsc --noEmit still reports existing package-wide type resolution issues unrelated to this patch

---

Summary by cubic

Prevents duplicate Resend templates by upserting on upload in @react-email/ui. Uses a stable alias and a paginated lookup to update existing templates, and updates the toolbar to show when a template was created vs updated.

• Bug Fixes
  • Added upsertResendTemplate to generate a deterministic alias and update existing templates; only creates when no match is found (with fallback to legacy names, including those with extensions).
  • Implemented paginated template lookup and selected the oldest exact name match when the alias isn’t present; tightened result narrowing for CI.
  • Switched single and bulk uploads to use normalized template names via removeFilenameExtension and the upsert flow; pass legacyName for migration.
  • Updated UI messaging to distinguish “created” vs “updated” and return/display the operation in results; added focused tests for alias generation, matching, and pagination.

^{Written for commit 355eaa4. Summary will update on new commits. Review in cubic}

[vercel]

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[changeset-bot]

🦋 Changeset detected

Latest commit: 355eaa4

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/ui	Patch
react-email	Patch
@react-email/editor	Patch

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[pkg-pr-new]

Open in StackBlitz

npm i https://pkg.pr.new/@react-email/ui@3278

commit: 355eaa4

[cubic-dev-ai]

2 issues found across 4 files

Confidence score: 3/5

• There is a concrete production risk in packages/preview-server/src/utils/resend-template-upsert.ts: new SDK calls (templates.get, templates.list, templates.update) may fail if current Resend API keys lack the required permissions, which could break template upsert behavior at runtime.
• The fallback lookup in packages/preview-server/src/utils/resend-template-upsert.ts only inspects the first 100 templates; without pagination, larger accounts may miss existing templates and create duplicates.
• Given one high-severity, high-confidence operational risk plus a medium data-consistency risk, this looks mergeable with caution rather than a low-risk merge.
• Pay close attention to packages/preview-server/src/utils/resend-template-upsert.ts - verify API key scopes for new template operations and add pagination to prevent duplicate template creation.

Prompt for AI agents (unresolved issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="packages/preview-server/src/utils/resend-template-upsert.ts">

<violation number="1" location="packages/preview-server/src/utils/resend-template-upsert.ts:162">
P1: Custom agent: **API Key Permission Check SDK Methods**

This change introduces new Resend SDK operations (`templates.get`, `templates.list`, `templates.update`). Confirm production API keys include permissions for template read/update operations, not just create, to prevent post-deploy permission failures.</violation>

<violation number="2" location="packages/preview-server/src/utils/resend-template-upsert.ts:188">
P2: Fallback lookup only checks the first 100 templates with no pagination, so existing templates outside that page won’t be found and a duplicate can be created for large accounts.</violation>
</file>

_{Reply with feedback, questions, or to request a fix. Tag @cubic-dev-ai to re-run a review.}

[cubic-dev-ai]

0 issues found across 1 file (changes from recent commits).

_{Shadow auto-approve: would require human review. Introduces non-trivial logic for template upserting, deterministic hashing, and paginated API lookups, which requires human verification of the migration and matching strategy.}

[gabrielmfern]

seems overly complicated at the upsert part

[gabrielmfern]

why do we need this and aren't just using the native node SDK?