Choose the Worker mail flow: direct SMTP or the Resend API.

Worker Mailer gives you two delivery paths for Cloudflare Workers. Use SMTP when you need socket-level transport, DSN, hooks, attachments, and CID inline assets. Use Resend when you want a fetch-based provider flow with the same Worker-friendly message and queue patterns.

What ships today

Open source illustration adapted to the worker-mailer palette.

SMTP covers direct Worker delivery with TCP sockets, HTML and text bodies, attachments, CID assets, DSN, and lifecycle hooks.
Resend keeps the same Worker-first send flow over the Resend API when you prefer provider-managed delivery.
Both packages include Bun-first setup, Cloudflare Queues helpers, and EmDash sandbox bundle docs.

@workermailer/smtp

SMTP

Developer-first documentation for @workermailer/smtp on Cloudflare Workers.

Open SMTP docs Changelog

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Guides

@workermailer/resend

Resend

Developer-first documentation for @workermailer/resend on Cloudflare Workers.

Open Resend docs Changelog

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Guides