site.support.google.com: Gmail Send mail as with your own domain, and why it stops working in 2027

How Send as works per Google's help page, what makes it fail SPF and DKIM, and how to send from a custom domain once Gmail drops it for third-party addresses.

Published by: MarkRelay Research
Updated: October 25, 2026
Sources: 5 primary sources, linked below

Summary

Gmail's Send mail as lets you pick another address in the From field after Gmail confirms you own it with a verification email; for addresses outside Google it needs the other provider's SMTP server, and replies still go to your Gmail address unless you set a reply-to. Mail sent this way passes SPF and DKIM only if that SMTP server is authorized for your domain, and Gmail and Yahoo require the From domain to align with one of them for bulk mail. Google's help page now says that from January 2027 Gmail will no longer support Send as for third-party addresses; Workspace aliases are not affected. For a domain on Cloudflare, the lasting setup is to send through Cloudflare Email Sending, which signs for the domain itself, for example from MarkRelay's webmail.

Key findings

1Send as adds an address to Gmail's From menu after a confirmation email to that address.
2Addresses at other providers need that provider's SMTP server, over SSL or TLS with a valid certificate.
3Changing only the From address keeps replies going to your Gmail address unless you also set a reply-to.
4From January 2027 Gmail will no longer support Send as for third-party addresses; Workspace aliases and other Gmail addresses keep it.
5Bulk senders to Gmail and Yahoo need SPF and DKIM, with the From domain aligned with one of them.

Questions this report answers

Asked by real people, quoted as they wrote them.

“Using "send as" feature with gmail from custom domain not hosted by Google fails SPF and DKIM”

Super User

SPF passes only if the SMTP server you gave Gmail is in your domain's SPF record, and DKIM aligns only if that server signs with your domain's key. Use an outgoing server that is set up for the domain, or send from a host that signs for the domain; and plan for Send as for third-party addresses ending in January 2027.

“Domain at cloudflare, send email from hello@mydomain.com via gmail?”

r/CloudFlare

Cloudflare Email Routing only receives, so Gmail's Send as needs an SMTP service authorized for the domain. Cloudflare Email Sending is Cloudflare's own sending path and writes SPF and DKIM for the domain when you onboard it; MarkRelay gives it a webmail and API.

“Paying £120 a year for webhosting just to be able to use my domain (parked on cloudflare) email, is there a cheaper option?”

r/webhosting, 17 comments

Receiving is free with Cloudflare Email Routing. Sending as the domain costs $5 a month on Workers Paid with Email Sending, and MarkRelay adds a webmail for $99 a year; Gmail Send as with a free SMTP plan works only until January 2027.

“send email from custom domain free”

Google search suggestion

Gmail Send as with a free SMTP plan is the usual free route, until January 2027. Cloudflare Email Sending sends free only to verified addresses in your own account; to anyone else it needs Workers Paid.

How Send mail as works

Step	Per Google's help page
Add the address	In Gmail settings, under Send mail as
Outgoing server	The other provider's SMTP server, with SSL or TLS and a valid certificate
Prove ownership	Open the confirmation email Gmail sends to the address
Replies	Go to your Gmail address unless you set a reply-to
Third-party addresses	Not supported from January 2027

Add the address

Per Google's help page: In Gmail settings, under Send mail as

Outgoing server

Per Google's help page: The other provider's SMTP server, with SSL or TLS and a valid certificate

Prove ownership

Per Google's help page: Open the confirmation email Gmail sends to the address

Replies

Per Google's help page: Go to your Gmail address unless you set a reply-to

Third-party addresses

Per Google's help page: Not supported from January 2027

Source: Send emails from a different address.

Sending as a domain on Cloudflare

Option	Gmail Send as + SMTP plan	Email Sending from your Worker	MarkRelay$99/yr + Cloudflare
Works after January 2027	No	Yes	Yes
SPF and DKIM for your domain	Only if the SMTP provider is set up for it	Written by Cloudflare at onboarding	Written by Cloudflare at onboarding
Where you write and read mail	Gmail	Code you write	Webmail, HTTP API, MCP
Replies land in	Gmail, via forwarding	Wherever your code puts them	The same mailbox
Cost	Free tier of the SMTP plan	$5/month, 3,000 emails	$5/month + $99/year

Works after January 2027

Gmail Send as + SMTP plan: No
Email Sending from your Worker: Yes
MarkRelay: Yes

SPF and DKIM for your domain

Gmail Send as + SMTP plan: Only if the SMTP provider is set up for it
Email Sending from your Worker: Written by Cloudflare at onboarding
MarkRelay: Written by Cloudflare at onboarding

Where you write and read mail

Gmail Send as + SMTP plan: Gmail
Email Sending from your Worker: Code you write
MarkRelay: Webmail, HTTP API, MCP

Replies land in

Gmail Send as + SMTP plan: Gmail, via forwarding
Email Sending from your Worker: Wherever your code puts them
MarkRelay: The same mailbox

Cost

Gmail Send as + SMTP plan: Free tier of the SMTP plan
Email Sending from your Worker: $5/month, 3,000 emails
MarkRelay: $5/month + $99/year

Source: Cloudflare Email Routing troubleshooting, Cloudflare Email Service pricing.

Why Send as fails SPF and DKIM

SPF checks whether the sending server is listed in your domain's SPF record; DKIM checks a signature made with a key published on your domain. When Gmail relays through an SMTP server that is not listed in your SPF record and does not sign with your domain's key, both fail, and since Gmail's and Yahoo's sender rules require alignment with the From domain for bulk mail, the message is more likely to be filtered.

How MarkRelay sends as your domain

MarkRelay sends through Cloudflare Email Sending, so the signing happens on Cloudflare for the domain you onboarded: Cloudflare writes the SPF and DKIM records and, per its documentation, keeps DMARC alignment. You write from MarkRelay's webmail, or your app calls its HTTP API with a key limited to the mailboxes it may use.

Every sent message is kept in the mailbox's Sent folder, and because the same Worker receives the domain's mail, replies arrive in the same mailbox rather than in a separate Gmail account.

Where MarkRelay fits

A good fit when

Domains on Cloudflare that today rely on Gmail Send as and need a sending path after January 2027.
Several addresses or people answering from the same domain.

Look elsewhere when

Staying inside Gmail's interface: MarkRelay is its own webmail.
Domains not on Cloudflare DNS.

Common questions

Is Gmail removing Send mail as?

For third-party addresses, from January 2027. Send as for Workspace aliases and other Gmail addresses you own stays.

Why do replies to my Send as address go to Gmail?

Google's help page says replies go to your original Gmail address unless you also set a reply-to address.

Sources and method

Send emails from a different address (support.google.com/mail/answer/22370)
Changes to third-party account support (support.google.com/mail/answer/17101213)
Gmail sender guidelines (support.google.com/a/answer/81126)
Cloudflare Email Routing troubleshooting (developers.cloudflare.com/email-routing/troubleshooting/)
Cloudflare Email Service pricing (developers.cloudflare.com/email-service/platform/pricing/)

Facts are taken from each vendor's own pricing pages, documentation or terms as of the updated date above; prices are in US dollars per month unless stated. Cost comparisons apply each vendor's published rates to the same volume. MarkRelay is not affiliated with Google;"site.support.google.com" in the title names the site these facts come from. MarkRelay sells a self-hosted email app, which this page mentions where it fits. Spotted something outdated? Tell us.

Revisions

October 25, 2026: First published; every fact checked on the vendor's own pages.