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Cloudflare Email Service Now Speaks Authenticated SMTP!

Cloudflare Changelog ★★★ View Markdown
#cloudflare#serverless#web

Hey there, it's me, Shii-chan! Today I've got a little update that makes sending email nicer.

Cloudflare Changelog developers.cloudflare.com

What was announced?

Cloudflare's Email Service now offers authenticated SMTP submission in beta! This one showed up on the Cloudflare Changelog. You connect to smtp.mx.cloudflare.net on port 465 and send mail over plain old SMTP.

The story so far

Until now, Email Service gave you two ways to send: the REST API and the Workers binding. Both are handy, but if your app already spoke SMTP, you had to rewrite the sending part to switch over.

What changes

With SMTP as a third entry point, any app that already speaks SMTP can point straight at Cloudflare. Language-native libraries like Nodemailer, smtplib, PHPMailer, and JavaMail work as-is, so you just swap the endpoint and credentials and move over. Nice, right!

Dive Deep

Here's how you connect:

Host: smtp.mx.cloudflare.net
Port: 465 (implicit TLS)
Auth: PLAIN or LOGIN

For credentials you use an API token with the "Email Sending: Edit" permission, and it supports PLAIN or LOGIN authentication.

Even when you send over SMTP, the delivery infrastructure is the same as the other methods: automatic DKIM and ARC signing, plus shared dashboard logs. The rate limits are shared across submission methods too, so nothing changes behavior on you midway. The finer setup details live in the SMTP submission guide.

Wrap-up

  • Cloudflare Email Service adds authenticated SMTP submission in beta (smtp.mx.cloudflare.net:465, implicit TLS)
  • Authenticate with an API token holding the "Email Sending: Edit" permission; PLAIN / LOGIN supported
  • Delivery infra is shared with the REST API / Workers binding, so DKIM/ARC signing, logs, and rate limits all match
  • Existing SMTP apps like Nodemailer, smtplib, PHPMailer, and JavaMail can move over with minimal rewriting

This one lands especially well for anyone who already has email-sending code and wants to consolidate it on Cloudflare!

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