Choosing a Sending Domain and From Address for Emails

Every email your SaaS sends shows a name and an address in the From line. Choosing a sending domain and from address is a small decision, but people see it every time, and it's awkward to change once emails are live.

This guide is for people building SaaS products, sites and tools with Claude Code who want to settle these choices before going live. It gives you a clear recommendation for each piece, examples you can copy, and the message to send Claude Code once you've decided.

Choosing a sending domain: your main domain or a subdomain?

Use a subdomain of the domain you already own, such as mail.yourcompany.com. That's the usual recommendation for transactional emails, the ones a SaaS sends automatically (see what a transactional email service does).

Your sending domain is the part after the @ in your from address. You have three options:

Steer clear of lookalike domains. Resend's documentation notes they can look suspicious to inbox providers and confusing to the people receiving them. A subdomain carries your real domain name, so people can see it's you.

Whichever you pick, you'll verify it by adding a few DNS records (small settings attached to your domain) where your domain is registered. This shows inbox providers your email service may send for you, and Gmail's sender guidelines require it. Our guide on how to verify a domain for email walks through it.

Should you use a subdomain like mail. or notify.?

Yes. A subdomain keeps your SaaS's emails separate from your team's everyday email, and you add the records your email service needs without touching the ones your inbox depends on.

Resend's documentation adds that if something goes wrong with your sending, such as a flood of fake sign-ups causing thousands of bounced emails, the trouble stays with the subdomain rather than your main domain. A subdomain named for its purpose also helps inbox providers understand what kind of email it sends.

Pick a short, plain name that says what the emails are: mail., notify. and account. are all common. Most SaaS products need one sending subdomain, not several. Stick with the one you choose, because switching later means verifying a new subdomain.

How do you choose a from name and address?

Use your product's name as the from name, and a short, friendly address on your sending subdomain. For example: YourCompany, hello@mail.yourcompany.com.

The from name is what people see first in their inbox. Gmail's guidelines say it should identify the sender clearly and consistently:

• Use the name people know your product by.
• Keep the subject out of the name. "YourCompany" works; "YourCompany: Action needed" doesn't.
• Skip emojis and symbols in the name.
• If you want a personal touch, "Sam at YourCompany" works, as long as it's a real person on your team.

The from address should use a word that reads well, such as hello, team or account. Gmail recommends that emails of the same kind always come from the same address, so keep it consistent. A setup that works for most SaaS products:

noreply or a real reply address?

Use a real address that someone checks, not a noreply email address. People reply to transactional emails often, to ask why a payment failed or say a reset link didn't work.

The fix is a reply-to address. Under the email standard (RFC 5322), when an email has a reply-to address, replies go there instead of to the from address. So you can send from hello@mail.yourcompany.com and have replies land in support@yourcompany.com, the inbox your team already uses.

This matters even more on a subdomain, because addresses there usually aren't real inboxes you can open. Without a reply-to, a reply could go nowhere.

A noreply address also tells users you don't want to hear from them, while a reply-to keeps the conversation open. If your SaaS has a contact form, the same idea applies there; see how to make your contact form send emails.

How do you set it up?

Setup happens in two places: the SimpleSends website, where you verify your sending domain, and the Claude Code chat, where you tell Claude Code which name and addresses to use.

1. Sign up on the SimpleSends website and follow the steps there to set up the email address you'll send from. To send from your own domain or subdomain, this includes adding a few DNS records where your domain is registered.
2. In Claude Code, open Customize, then Connectors, choose Add, then Add custom connector. Name: SimpleSends. MCP server URL: https://mcp.simplesends.com/mcp. (A connector, built on MCP, lets Claude Code work with an outside service while you build.)
3. When Claude prompts you to connect, log in to SimpleSends.
4. Back in the Claude Code chat, tell Claude Code: "I've connected SimpleSends for all transactional email." It takes it from there, including adding what your project needs to send email.

Then tell Claude Code your choices, the way you'd brief a person:

Please send all our transactional emails from YourCompany at hello@mail.yourcompany.com, and set the reply-to to support@yourcompany.com so replies reach our team. Use the same from name and address for every email. Send me a test so I can see how it looks in my inbox.

Claude Code sets the sender details in your project and sends you a test. In your inbox, the name should read YourCompany, and hitting reply should address the email to support@yourcompany.com.

From there, Claude Code can build each email your SaaS needs with the same sender details. See the transactional emails every SaaS needs for what's next.