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← Transactional Email Deliverability Core

Build Transactional Email Deliverability Core on nextjs-postgres-resend

Production transactional email machinery for a Next.js app: Resend integration behind a provider seam, local suppression list with correct bounce/complaint semantics, signature-verified webhooks, a domain warmup governor, staged DKIM/SPF/DMARC rollout with an automated DNS checker, and a template preview/test harness — with the tests already written.

This build pack is pinned for nextjs-postgres-resend, with verification pending. No pass rate is published until the harness runs it.

Coming soon — $79

nextjs-postgres-resend versions lock

node24.18.1
next16.2.12
react19.2.8
react-dom19.2.8
typescript6.0.3
resend6.18.1
svix1.99.1
pg8.22.0
@electric-sql/pglite0.5.4
vitest4.1.10

What you get

Features:

  • `sendEmail()` pipeline: suppression check → warmup cap → template render →

Resend send (idempotency-key passthrough) → event log, in that order

  • Provider seam (`EmailProvider` interface) — swap Resend for Postmark/SES by

writing one class; a mock provider ships for tests and local dev

  • Suppression list in your own Postgres with non-negotiable semantics

(complaints permanent and non-removable; soft bounces never suppressed)

  • Svix-signature-verified webhook endpoint, idempotent on the delivery id,

auto-maintaining the suppression list from bounces and complaints

  • 45-day warmup ramp table with UTC day accounting; over-cap sends deferred

with their full send input stored, so they are replayable — never dropped

  • Staged DMARC rollout (none → quarantine → reject) with a checker CLI that

validates SPF, DKIM, return-path MX, and DMARC live or against fixtures

  • Two production templates (welcome, password-reset) with mandatory

plain-text parts, establishing the template pattern

  • Plain-SQL migration, append-only email event log for ops/debugging
  • Full vitest acceptance suite on in-process Postgres (PGlite) — no Docker
  • One-page human go-live checklist covering the only manual steps

Screens/pages:

  • `/dev/emails` — template preview gallery (subject, HTML iframe, text part),

disabled in production

  • `POST /api/webhooks/resend` — webhook endpoint (401 on bad signature)
  • CLI: `npm run check-dns` — per-record PASS/FAIL report with detail text

Prescribed services

Disclosure: some links on this page are affiliate links. We may earn a commission if you sign up through them, at no extra cost to you. We only link to services the pack actually verified against.