SMTP

Send email through the mail account or server you already have, for companies that don't use Microsoft 365.

Ask Claude to connect it

Included on every plan. An admin approves it once.

What your app can do with it

✓Works with a hosting provider's mailbox, a relay or your own server
✓The password is kept by Syntica, never in the app's code
✓Email can only leave the app once an admin has approved the connection

For your IT admin

Setting it up

Done once, in your company's own account with your mail provider.

Create or pick a send-only mailbox with the provider.

Note the host, port, username and password.

Prefer a dedicated mailbox. With most providers the same password also grants inbox access.

For developers

What your app receives

The ordinary SMTP path, for applications that do not run on Microsoft 365: a hosting provider’s mailbox, a relay, or your own server. The account stays the customer’s, and the platform holds the password and injects it at deploy time, so it never reaches the repository. Use the library your language already has, whether that’s nodemailer, smtplib, or whatever is idiomatic, and read SMTP_SECURE as a string: implicit TLS on port 465, STARTTLS everywhere else. Outbound SMTP is closed until the grant exists: an application without an SMTP connection for that environment cannot reach ports 25, 465 or 587 on any outside server, so a pasted password goes nowhere. The rule is reapplied on every deploy, and a grant takes effect with the next one. HTTPS mail APIs are not affected.

SMTP's own documentation →

SMTP_HOSTSMTP_PORTSMTP_SECURESMTP_USERSMTP_PASSMAIL_FROM