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Gmail Send Email as Different Address: 2026 Setup Guide

Send mail from a different address inside Gmail using the built-in send-as alias. Exact steps, SMTP setup, mobile limits, and the deliverability fix nobody mentions.

Alexis Dollé By Alexis Dollé · ·
Gmail Send Email as Different Address: 2026 Setup Guide

Google quietly raised the bar on Gmail sender authentication through 2024 and 2025, pushing strict SPF, DKIM and DMARC alignment for anyone sending volume mail, and the side effect is that the old “just add another address and hit send” approach now bites you on deliverability if you skip a single setting. The good news is that Gmail still ships a free send-as feature that supports up to 99 different addresses per account, and once you wire one correctly it works for years. I set up three send-as aliases on a working account, one through Gmail’s relay and two through external SMTP servers, and watched which messages landed in inbox versus tagged “on behalf of” in Outlook. Here is the exact path through Settings, the SMTP step that fixes the deliverability headache, and the mobile limitation you need to plan around.

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What “send as a different address” actually means in Gmail

Gmail’s send-as feature lets you compose and reply from an email address other than your primary Gmail, while still sending through the Gmail interface. You add the address under Settings, Accounts and Import, “Send mail as”, verify you own it, and from then on the alias appears in the From dropdown when composing.

People mean three different things when they ask how to “send email as a different address” in Gmail, and the setup path is different for each.

The first is plus-addressing, where yourname+shop@gmail.com is a receiving label on your existing mailbox. It needs no setup, but you cannot actually reply as the plus-address: Gmail will always show your real address in the From field. Plus-addressing is a sorting tool, not a sending identity. If that is what you actually need, our walkthrough on how to set up a Gmail alias covers the plus-address and dot-variation tricks in detail.

The second is a true send-as alias: a genuinely separate address you own, added under Gmail’s account settings so the From dropdown shows it as a sender option. This is what most people mean and what the rest of this guide covers.

The third is “send on behalf of” through Workspace, where an executive grants an assistant the ability to send from the executive’s address. That is a separate delegation feature with its own permission flow, not the same as send-as, and it only exists inside Google Workspace.

For 99 percent of “I want to send from my custom-domain address inside Gmail” or “I want to reply from my freelance alias without leaving Gmail” cases, the send-as setup is the answer. It is free on personal Gmail and Workspace alike, and Google’s documentation confirms you can add up to 99 distinct send-as addresses on a single account [1].

Step-by-step setup on the desktop web Gmail

To send from a different address in Gmail, open Settings, then Accounts and Import, then in “Send mail as” click “Add another email address”. Enter the name and address, choose between Gmail relay or an external SMTP server, click “Next Step” and “Send verification”, then open the verification mail at the other address and click the link or paste the code back into Gmail.

Here is the exact path, taken from Google’s support documentation and walked through on a fresh account [1]:

  1. Open Gmail in a desktop browser. Click the gear icon in the top right, then See all settings.
  2. Open the Accounts and Import tab (called Accounts inside Google Workspace).
  3. Scroll to the Send mail as section. Click Add another email address.
  4. In the popup, enter the Name you want shown to recipients and the Email address of the alias. Leave Treat as an alias checked if both addresses are yours and you want one unified inbox; uncheck it for shared mailboxes (more on this below).
  5. Click Next Step.
  6. Choose how Gmail should send the message. The simple option is to leave Gmail’s relay selected. The recommended option, especially for custom-domain addresses, is to enter the alias’s own SMTP server, port, username and password.
  7. Click Next Step, then Send verification.
  8. Open the alias’s inbox. Click the verification link in the message from send-as-noreply@google.com, or copy the code and paste it back into Gmail.
  9. Done. The alias is now selectable in the From dropdown every time you compose.

Two settings inside the same Send mail as block turn this from a novelty into a real workflow. First, toggle “Reply from the same address the message was sent to” so that when someone mails the alias, your reply automatically goes out as the alias rather than your primary Gmail. Without this you will leak your real address on the first reply and confuse the recipient.

Second, if you want the alias’s incoming mail to land in this Gmail inbox too, add it under Check mail from other accounts in the same Accounts tab. That step is separate from send-as: send-as covers outbound only, and inbound pull is its own configuration.

If the verification message never arrives, check the alias’s spam folder for mail from send-as-noreply@google.com [1]. That single source accounts for most “I cannot get the code” support threads.

SMTP server or Gmail relay, which to pick

Pick Gmail’s relay when the alias is another Gmail or a hobby address where you do not control DNS. Pick the alias’s own SMTP server when the alias is a custom-domain mailbox you care about, because relaying through Gmail can trigger “on behalf of” tags in Outlook and weakens SPF and DMARC alignment on the alias domain.

This is the setting almost everyone gets wrong, and it is the one that quietly costs you deliverability. The popup gives you two options after you enter the address: send through Gmail’s servers, or send through the alias’s own SMTP server. The default is the Gmail relay because it requires zero technical setup, and that default works fine for low-volume personal use.

But for custom-domain addresses, it has two real costs. First, some recipients on Outlook see the message tagged as “From yourname@gmail.com on behalf of alias@yourdomain.com” in the sender field, because Gmail stamps your real address in the underlying Sender header [1]. This looks unprofessional and confuses recipients who do not recognise the Gmail address.

Second, the message is being sent from Gmail’s IP range with Gmail’s authentication, not your domain’s. If the alias domain has strict SPF, DKIM and DMARC records, the alignment can fail and stricter inboxes may flag the mail or send it to spam. This matters far more now than it did pre-2024, because Google itself tightened the bulk-sender authentication rules across Gmail in February 2024 and pushed them further through 2025.

The fix is to use your alias’s own SMTP server. For most custom-domain mailboxes that means entering the host (something like smtp.yourprovider.com), the port (usually 465 for SSL or 587 for TLS), and your mailbox username and password. Gmail then sends through that server, the message comes out cleanly authenticated to the alias domain, and the “on behalf of” tag vanishes.

I tested this with a custom-domain address routed through three different setups: Gmail relay only, alias SMTP on port 465 SSL, and alias SMTP on port 587 TLS. Both SMTP paths sent clean mail with no “on behalf of” tag in Outlook 2024. The Gmail relay path triggered the tag on Outlook for Windows but not on the Outlook web client, which is the kind of inconsistency you do not want for client-facing mail.

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How to actually send from the alias once it is added

Once the alias is verified, click Compose in Gmail, then click the From field at the top of the new message and pick the alias from the dropdown. To make every reply to that alias automatically go out as the alias, enable “Reply from the same address the message was sent to” in the Send mail as block.

The send-as alias is invisible in Gmail until you actually use it. Three places to know about.

In the compose window, click the From field at the top of the new message. A dropdown appears with your primary address plus every verified send-as alias. Pick the alias and send normally. The recipient sees only the alias in the From line, assuming you set up SMTP correctly.

When replying to a message, Gmail picks the From address based on your reply-from setting. With “Reply from the same address the message was sent to” enabled, a message sent to the alias is replied to from the alias automatically. Without it, every reply defaults to your primary Gmail, even for mail addressed to the alias. Almost nobody wants the default; turn this on once and forget it.

For default sending, you can mark any alias as the default in the Send mail as block. That alias becomes the From address for every new compose unless you switch it manually. Useful if you mostly send as the alias and rarely as your primary Gmail, less useful for a 50-50 split.

One workflow trap worth naming: if you reply to a message and then change the From address mid-compose, Gmail keeps the original recipient list but may shift the conversation thread in a way that confuses long email chains. Cleanest practice is to pick the From address first, then write, then send, rather than switching mid-draft. This matters mostly on long threaded conversations; for one-off mail it makes no difference.

Pairing this with strong inbox hygiene helps the alias workflow actually save time. Our guide to a weekly inbox cleanup routine walks through the recurring sweep that keeps a multi-identity inbox from drowning in months of accumulated mail.

The Gmail mobile app limitation

The Gmail iOS and Android apps do not expose a From dropdown in the compose window, so you cannot pick a send-as alias the way you can on desktop. The two real workarounds are to add the alias as its own account in the mobile app and switch accounts before composing, or to defer alias mail to desktop sessions.

This is the single biggest gap in Gmail send-as, and Google has not closed it. The mobile apps treat each Gmail account as its own profile and let you swipe between them, but they do not surface verified send-as addresses inside any one account.

In practice that means a custom-domain address you added to your primary Gmail via send-as is fully usable in the web browser, including the mobile web browser, but invisible in the dedicated Gmail mobile app for that same account. You can still receive its mail if you set up Check mail from other accounts, but every reply will go out from your primary Gmail address unless you switch.

Three workarounds, in order of how well they hold up:

  1. Add the alias as its own account in the Gmail mobile app, separately from your primary Gmail. The two appear as switchable accounts in the side menu, and composing while on the alias account sends as the alias. This is clean but only works if the alias has its own real mailbox (a Workspace user, an IMAP-accessible mailbox, etc.) — not for plain plus-addresses.
  2. Open mail.google.com in the mobile browser. The mobile web Gmail does show the From dropdown when composing, just like desktop. Slower than the app, but it works for the occasional reply on the go.
  3. Defer alias mail to desktop sessions. If you only send a handful of alias-mail messages a week and they are not urgent, just leave them for your next desktop session.

I leaned on workaround 1 for a freelance-brand alias for a year and it was fine for everyday use. The seam shows when you reply to a notification in the wrong account by reflex — the answer always goes out from whichever account was selected when you tapped reply. Slow down before composing replies that need the alias identity.

”Treat as an alias”, checked or unchecked

Leave “Treat as an alias” checked when both addresses are yours and you want them to share one unified inbox, sent folder and threading. Uncheck it when the other address belongs to a separate person, a shared mailbox, or an organisation, and you only want to send on its behalf without merging the two identities.

This single checkbox confuses more Gmail send-as users than the SMTP question, because the consequences only show up later. Workspace’s own documentation lays the choice out plainly [2].

Checked (the default) means Gmail treats the added address as just another label on your inbox. Messages sent to the alias and to your primary Gmail share threading. The Sent folder shows the message regardless of which address sent it. Replies populate the To field with the original recipients, as if both addresses were the same person — because functionally, they are.

Unchecked means Gmail treats the added address as a separate account that you happen to send on behalf of. Threading splits. Replies populate the To field with the sender of the message you are replying to, rather than the conversation chain. You are signing on someone else’s behalf, not as yourself.

Practical rules:

  • A personal you@yourdomain.com added to your you@gmail.com → check it. They are both you.
  • A team@startup.com shared mailbox added to your personal Gmail so you can answer support tickets → uncheck it. Replies need to go to the customer, not flow back into the shared mailbox conversation.
  • An executive’s address added by an assistant via delegation → uncheck it. The assistant is sending on the exec’s behalf, not as the exec.

Get this wrong on a shared mailbox and replies start landing in the wrong place; get it wrong on a personal alias and your sent mail shows up in confusing duplicate threads. Five-second decision, but check it once at setup rather than fighting odd behaviour for months.

If you are managing several mail identities across Gmail and other clients, the broader picture of organising the resulting flow is worth thinking through — our walkthrough on organising email archives covers the labels, folders and retention rules that keep a multi-address setup from sprawling.

Where Gmail send-as stops working

There is an honest boundary to send-as, and naming it stops you from trusting it with the wrong job.

  • No From dropdown in the Gmail mobile app. Native iOS and Android compose windows hide the alias entirely. Add the alias as a separate account in the app, use the mobile browser, or defer.
  • Verification requires you to actually own the alias. Google will not let you send as an address you cannot open. If you have lost access to the alias mailbox you cannot complete setup.
  • Default Gmail relay can trigger “on behalf of” tags in Outlook. Set up your alias through its own SMTP server to avoid it, especially for client-facing mail.
  • Strict SPF, DKIM and DMARC on the alias domain can flag relay mail. Since Google’s 2024 bulk-sender authentication tightening, the safer default for any custom-domain alias is to send through the alias’s own SMTP server, not Gmail’s relay.
  • Up to 99 send-as addresses per account, then no more. Well above what almost anyone needs, but worth knowing if you are running a heavy multi-brand setup.
  • No delegation under personal Gmail. Workspace lets you grant another user the right to send on your behalf. Personal Gmail does not. If you need a real assistant workflow, you need Workspace.
  • No SMS or in-app reply notification specifies which alias was hit. You see “new mail” without the alias label unless you build a Gmail filter that tags by To address.

Send-as is the right tool for outbound identity. It is the wrong tool when you need real isolation, a separate inbox, or someone else legally sending under your name.

The verdict: a setup that holds up

The setup that holds up over time is one send-as alias per identity you actually need to write from, configured with the alias’s own SMTP server, “Reply from the same address” turned on, and “Treat as an alias” checked for your own addresses and unchecked for shared mailboxes. Mobile gaps are real; plan to send alias mail from the desktop or web.

Working through every option against real mail, the rules that pay off are short:

  1. Use send-as for any address you write from often enough that switching accounts is friction. Custom-domain mail, freelance brands, side projects, work mail you want pulled into one window.
  2. Always configure the alias’s own SMTP server when the alias is a custom domain. It takes five extra minutes at setup and avoids the “on behalf of” tag plus the 2024-tightened authentication penalties.
  3. Turn on “Reply from the same address the message was sent to”. This is the one toggle that makes the alias feel native instead of leaky.
  4. Pick the “Treat as an alias” checkbox deliberately. Checked for your own addresses, unchecked for shared mailboxes and on-behalf-of flows. Five seconds at setup, no headaches later.
  5. Plan around the mobile app gap. Add the alias as its own account in the app, use the mobile browser, or just send alias mail from the desktop.

The shortest version: send-as is free, it scales to 99 addresses, it works for years once configured, and the only common failure modes are SMTP misconfiguration and the mobile app’s missing From dropdown. Get both right and you have a clean multi-identity Gmail that takes minutes to set up and never needs touching again.

Alexis Dollé, founder of Email Tools
Alexis Dollé
Founder & Editor

Alexis Dollé, email expert for 10+ years. Founder of Email Tools. I test every email client and utility myself, then write about them the way I’d explain them to a friend — no marketing fluff, no sponsored rankings, every claim sourced.

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Sources & references
  1. Google — Send emails from a different address or alias. Steps for adding a send-as address under Settings, Accounts and Import, the verification flow, SMTP server option, up to 99 send-as addresses per account, and the “on behalf of” Outlook behaviour. Accessed 2026-05-23. support.google.com/mail/answer/22370
  2. Google Workspace Admin Help — Should I uncheck “Treat as an alias” in Gmail. Behaviour of the Treat as an alias setting, when checked vs unchecked, shared mailbox guidance, and reply-recipient differences. Accessed 2026-05-23. knowledge.workspace.google.com/admin/users/should-i-uncheck-treat-as-an-alias-in-gmail
  3. Email Tools — How to set up a Gmail alias. email-tools.me/en/gmail-alias-setup/
  4. Email Tools — Weekly inbox cleanup routine. email-tools.me/en/inbox-cleanup-routine-weekly/
  5. Email Tools — How to organise email archives. email-tools.me/en/how-to-organize-email-archives/

Frequently asked questions

Can I send a Gmail message as a different address? — yes, via send-as

Yes. Open Gmail Settings, then Accounts and Import, and under ‘Send mail as’ click ‘Add another email address’. Enter the address you own, verify it with the code or link Google sends, and it appears in the From dropdown every time you compose. Gmail lets you add up to 99 send-as addresses on a single account, and the feature is free on personal Gmail and Google Workspace alike. It only works on the desktop web Gmail interface for setup; once configured, the alias is available from the From dropdown when composing in a browser.

Difference between an alias and a send-as address? — receiving vs sending

A plus-address like yourname+shop@gmail.com is a receiving label on your existing mailbox, set up by typing. A send-as address is a genuinely separate email address you own elsewhere (a work address, a custom-domain mailbox, another Gmail) that Gmail lets you both pull mail from and send from. Only the send-as version lets you reply with the other address shown in the From field. Both are free, both land in your inbox, but only send-as changes the identity recipients see.

Why does Gmail say ‘on behalf of’ when I send from an alias? — relay header

Some recipients, especially older Outlook clients, see ‘From yourname@gmail.com on behalf of alias@otherdomain.com’ because by default Gmail relays the message through its own servers and stamps your real address in the Sender header. The fix is to send the alias through its own SMTP server during setup, which Gmail offers as an option in the same Add another email address flow. After that, the message goes out cleanly with only the alias address visible, and the ‘on behalf of’ line disappears.

Can I send as a different address from the Gmail mobile app? — only with workarounds

Only partially. The Gmail iOS and Android apps do not let you pick a send-as alias from a From dropdown when composing. Your workarounds are to add the alias as a separate account in the mobile app and switch to it before composing, or to compose from the desktop web Gmail. Setup of any new send-as alias must be done on the desktop web Gmail too: the mobile apps do not expose the Accounts and Import settings.

Should I check ‘Treat as an alias’ in Gmail send-as? — depends on ownership

Check it when both addresses are yours and you want one unified inbox with shared sent mail and threading. Uncheck it when the other address belongs to a separate account or organisation and you only want to send on its behalf, keeping the two mail flows fully separate. For most personal users adding a custom-domain address, checked is the right default; for shared mailboxes, uncheck so replies go back to the original sender instead of being treated as the same identity.

Is sending from a different address in Gmail free? — yes, no tier gate

Yes. Adding a send-as address costs nothing on personal Gmail or Google Workspace. You only pay for the mailbox itself if the alias is on a paid domain or hosted elsewhere. Google does not cap the feature behind a tier, and you can add up to 99 distinct send-as addresses on a single account. The only ongoing cost is whatever your domain registrar or external mail host charges for the underlying mailbox.

Related: How to set up a Gmail alias — receiving aliases via plus-addressing and dot variations. Weekly inbox cleanup routine — keeping a multi-identity inbox from drowning. How to organise email archives — labels and folders for a multi-address setup.