HTTP API
Gmail, Microsoft 365, and Amazon SES can send over their own HTTPS API. Nothing depends on an SMTP port being open on your server, which many hosts block.
Your email provider, whichever it is
Gmail, Microsoft 365, and Amazon SES have their own connections, over their HTTP API or SMTP. Every other provider works through the Custom SMTP connection, with the server settings on its page.
- and 8 more below
Every provider
Delivery
16 of 16
- Gmail / Google WorkspaceSMTPAPIOAuth
- Microsoft 365 / OutlookAPIOAuth
- Amazon SESSMTPAPI
- Zoho MailSMTP via Custom SMTP
- SendGridSMTP via Custom SMTP
- MailgunSMTP via Custom SMTP
- PostmarkSMTP via Custom SMTP
- BrevoSMTP via Custom SMTP
- SparkPostSMTP via Custom SMTP
- MailerSendSMTP via Custom SMTP
- MandrillSMTP via Custom SMTP
NetcoreSMTP via Custom SMTP- SendLayerSMTP via Custom SMTP
SMTP2GOSMTP via Custom SMTP- SMTP.comSMTP via Custom SMTP
Elastic EmailSMTP via Custom SMTP
Anything else? Use Custom SMTP.
Any provider or host that gives you SMTP details works with the Custom SMTP connection: host, port, encryption, username and password. Set up Custom SMTP
Three ways to connect. Each provider uses the one that suits it.
OAuth sign-in
Gmail and Microsoft 365 connect by signing in with an app you create in your own Google Cloud or Microsoft Entra account. No mailbox password is stored on your site; BooleanSMTP keeps the sign-in refreshed.
SMTP
Every other provider, and your host’s own mail server, works through the Custom SMTP connection: a host, a port, encryption and a login. The settings for each provider are in the table below.
The native connections, side by side
What each one sends over, how it signs in, and what to have ready. The field names are the ones the plugin asks for.
| Provider | Sends over | Signs in with | Have ready | Guide |
|---|---|---|---|---|
| Gmail / Google Workspace | SMTP or HTTP API | Sign in with Google (OAuth), or an app password for SMTP | App Password, Client ID, Client Secret | Setup guide |
| Microsoft 365 / Outlook | HTTP API | Sign in with Microsoft (OAuth) | Client ID, Client Secret, Tenant ID | Setup guide |
| Amazon SES | SMTP or HTTP API | Access keys for the API, SMTP credentials for SMTP | SMTP Region, SMTP Username, SMTP Password, API Region, API Access Key ID, API Secret Access Key | Setup guide |
SMTP settings for every provider. Checked against each provider’s own documentation.
Enter these in a Custom SMTP connection. Each provider’s page says what its username and password are, and where to find them.
| Provider | SMTP host | Port and encryption | Username |
|---|---|---|---|
| Zoho Mail | smtp.zoho.com, smtppro.zoho.com | 587 TLS, 465 SSL | Your SMTP login, from the provider’s dashboard |
| SendGrid | smtp.sendgrid.net | 587 TLS, 2525 TLS, 465 SSL | apikey |
| Mailgun | smtp.mailgun.org, smtp.eu.mailgun.org | 587 TLS, 2525 TLS, 465 SSL | Your SMTP login, from the provider’s dashboard |
| Postmark | smtp.postmarkapp.com | 587 TLS, 2525 TLS | Your SMTP login, from the provider’s dashboard |
| Brevo | smtp-relay.brevo.com | 587 TLS, 2525 TLS, 465 SSL | Your SMTP login, from the provider’s dashboard |
| SparkPost | smtp.sparkpostmail.com, smtp.eu.sparkpostmail.com | 587 TLS, 2525 TLS | SMTP_Injection |
| MailerSend | smtp.mailersend.net | 587 TLS | Your SMTP login, from the provider’s dashboard |
| Mandrill | smtp.mandrillapp.com | 587 TLS, 2525 TLS, 465 SSL | Your SMTP login, from the provider’s dashboard |
| Netcore | smtp.netcorecloud.net | 587 TLS, 2525 TLS | Your SMTP login, from the provider’s dashboard |
| SendLayer | smtp.sendlayer.net | 587 TLS | Your SMTP login, from the provider’s dashboard |
| SMTP2GO | mail.smtp2go.com | 587 TLS, 2525 TLS, 8025 TLS, 80 TLS, 465 SSL, 8465 SSL, 443 SSL | Your SMTP login, from the provider’s dashboard |
| SMTP.com | Your account’s own server | 2525 TLS, 2082 TLS, 465 SSL | Your SMTP login, from the provider’s dashboard |
| Elastic Email | smtp.elasticemail.com | 2525 TLS, 587 TLS, 465 SSL | Your SMTP login, from the provider’s dashboard |
Choosing a provider
Which provider should I choose?
If your business email already runs on Google Workspace or Microsoft 365, sending through it is the simplest start. For a store or anything that sends in volume, a sending service such as Amazon SES suits better. The chooser on the features page ranks the setups for your site in four questions.
Can I use two providers at once?
Yes, and that is the point: one connection is your default and another is your fallback. When the default provider refuses a message, the fallback sends it straight away. You can add more connections, and each From address belongs to one of them.
My provider is not on this page. Will it work?
If it gives you SMTP details (host, port, encryption, username and password), yes: use the Custom SMTP connection. That covers most sending services and nearly every web host’s mail server.
How do Zoho Mail and the others connect?
Through the Custom SMTP connection, with the server, port and login on each provider’s page. Logging, the fallback, retries and alerts work for it exactly as for every other connection.
Which one should I pick?
Answer four questions and see the setups that fit your site, on the features page.