@nestjs-modules/mailer@4.0.0

Major Changes

• #1353 c8c0423 Thanks @juandav! - v4: everything the official @nestjs/mail offers and more, without dropping anything v3 supports. Every capability is optional: use nodemailer, the built-in HTTP providers or @nestjs/mail's transports; send directly, through BullMQ or through @nestjs/outbox; call sendMail, mail classes or the official Mailer over this module.

  Breaking changes (see the migration guide):

  • Transient failures are retried by default (3 attempts with backoff); retry: false restores v3. A timeout or a dropped connection while the message was being handed over is retried only when the email has a stable Message-ID (idempotencyKey), so nothing is sent twice. sendTimeout applies per attempt.
  • Errors from transports are typed (MailerSmtpError, MailerTimeoutError, … all MailerError), keeping nodemailer's fields and the original as cause; wrapErrors: false restores v3.
  • Emails without a text part get one derived from the HTML (textFromHtml: false to opt out), and messages are validated before sending (validate: false to opt out).
  • MailerTestModule delivers to a TestMailbox (no stream transport; info.message uses CRLF line endings) and defaults retry to false.
  • MailerPreviewModule is on by default only when NODE_ENV is development or test.
  • Event payloads carry attempt, permanent, transporterName and durationMs; MailerEventService takes its emitter through MAILER_EVENT_EMITTER, and EventEmitter2 is found automatically (in v3 it was never injected).
  • MailableContext.to is { name?, address }[], the same shape as @nestjs/mail.

  New

  • Mail classes (mailerService.send(WelcomeMail, { to, data })) compatible with @nestjs/mail's, with dependencies resolved from the whole app, and render() to render without sending.
  • Retries with backoff and error classification (nodemailer, HTTP and AWS SDK errors), failover between transporters, AbortSignal, idempotencyKey, and graceful shutdown that waits for sends in flight (shutdownTimeout).
  • Zero-dependency HTTP transports: Resend, Postmark, SendGrid, SES (SigV4), Mailgun and Brevo.
  • The html tagged template (unsafeHtml() for trusted markup), htmlToText() and message validation.
  • intercept (redirect recipients in staging), suppress (suppression lists) and one-click unsubscribe (RFC 8058).
  • TestMailbox with assertions, FileTransport and LogTransport (with a warning when used in production) and MailerPreviewModule to preview emails in the browser.
  • events$, node:diagnostics_channel publishing (credentials redacted), and RETRY, FAILOVER and SUPPRESSED events.
  • BullMQ: permanent failures fail the job at once, a stable idempotency key per job, schedule() and concurrency.
  • @nestjs-modules/mailer/nestjs-mail: NodemailerMailTransport, MailerServiceTransport and TemplateAdapterEngine for @nestjs/mail.
  • @nestjs-modules/mailer/outbox: transactional sending with @nestjs/outbox.
  • i18n falls back from a region to its language (es-CO → es) and searches every template directory.
  • Tested on NestJS 11 and 12.

  Fixed

  • Text-only emails no longer fail when a template adapter is configured.
  • intercept and suppress cover the whole custom envelope (to, cc and bcc).