Mail hosting · Transactional email · Marketing campaigns

Mail hosting, transactional email, and marketing campaigns — one platform.

Underline replaces your inbox provider, your transactional email API, and your marketing platform with one bill — and free corporate email hosting for your whole team.

Get started free See pricing

One platform, three products

Stop paying Google Workspace, SendGrid, and Mailchimp separately.

Mail

Free

Real IMAP/POP3 mailboxes on your own domain. Works with Outlook, Apple Mail, and any mobile mail app, plus a built-in web inbox.

Send

Paid

A transactional email API and SMTP relay with delivery tracking, webhooks, and per-domain DKIM/SPF setup — a SendGrid alternative built in.

Marketing

Paid

Mailing lists, segments, and campaigns with a template editor, merge tags, and open/click analytics — a Mailchimp alternative built in.

Free mail hosting is the whole point

We give away corporate email hosting because it gets your domain onto Underline. When you're ready to send receipts, invites, or newsletters, upgrade in one click — same platform, same team, same login.Create your organization