It will be great to see an authenticated tier and the pricing for it, I would want to add SPF and DKIM records but wouldn’t want anyone with access to workers to be able send emails from my domain

For a general guide to our pricing, check out https://www.mailchannels.com/pricing/. There isn't a way yet to send authenticated mail via the Cloudflare-oriented API; however, that will come. Paid users will get access to our console, click tracking, open tracking, priority support, etc.

Ah cool, looking forward to it. Thanks

Stay tuned to our blog for updates.

Wish this had SMTP credentials for legacy applications (even with an extra fee).

Noted! We will create an authenticated usage tier; however, we believe it's most convenient for Workers customers to mostly just use an unauthenticated request.