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+----- Thread: Guide What is BillionMail? A plain-English introduction (/Thread-guide-what-is-billionmail-a-plain-english-introduction)
What is BillionMail? A plain-English introduction - JAY - 10-21-2026
What is BillionMail? A plain-English introduction
BillionMail is a free, open-source mail server and newsletter platform made by the team behind aaPanel. It gives you two things in one install: a real mail server that sends and receives email, and a newsletter tool with contact lists, templates, campaigns and statistics.
Want to see it in action? Here is our full BillionMail on aaPanel video walkthrough:
If you have ever paid Mailchimp, Brevo or a similar service per subscriber, BillionMail is the self-hosted alternative: you pay for a server, and you can send as much as your server and your reputation allow.
What you get
- Email marketing: contact groups, CSV import, tags, HTML templates, scheduled campaigns (called "tasks"), and open, click and bounce statistics.
- Mailboxes and webmail: real addresses like support@ and admin@ on your domain, with Roundcube webmail and IMAP/SMTP for mail apps.
- Send API: let your website or app send receipts, password resets and other transactional email through it.
- SMTP relays: optionally hand delivery to Gmail, Mailgun, Amazon SES, SendGrid or any SMTP server.
- A DNS helper: it shows the exact MX, SPF, DKIM, DMARC and PTR records to add, and checks them for you.
What runs inside
BillionMail isn't a mail server written from scratch. It ties together well-known, trusted parts, each in its own Docker container:
- Postfix sends and receives mail.
- Dovecot stores mailboxes and serves IMAP and POP.
- Rspamd filters spam and signs outgoing mail with DKIM.
- Roundcube is the webmail.
- PostgreSQL and Redis store your data and keep things fast.
Who it's for
BillionMail is a good fit if you:
- send newsletters or product updates to people who signed up,
- want your subscriber list and statistics on your own server,
- are comfortable editing DNS records and reading an error message.
The honest part: deliverability is your job
Installing BillionMail takes about ten minutes. Getting Gmail and Outlook to trust your mail takes a bit more care. With a hosted service, they handle that for you. With your own server, you need:
- outgoing port 25 open at your VPS provider,
- correct DNS records: MX, SPF, DKIM and DMARC,
- a reverse DNS (PTR) record that matches your mail server name,
- a server that introduces itself with the right name (not "localhost"),
- a slow start (warm-up) on a new IP address, and a clean, opt-in list.
What you need to start
- A VPS with about 2 CPU cores and 4 GB RAM (it runs several containers).
- A domain where you can edit DNS.
- aaPanel installed (or Docker, if you prefer the command line).
Next steps
- Install BillionMail from aaPanel
- Set up DNS: MX, SPF, DKIM, DMARC and PTR
- Free SSL, and the hostname fix
- Send your first newsletter
- Test deliverability and fix problems
More BillionMail how-to guides
- Send API for transactional email
- WordPress email through BillionMail SMTP
- Import contacts, groups and tags
- Email templates explained
- SMTP relay with Amazon SES, Brevo or Mailgun
- Mailboxes and webmail
- Campaign analytics explained
- IP warm-up plan
- Move from Mailchimp or Sendy
- Add a second sending domain
Sources (checked October 2026): BillionMail on GitHub ยท billionmail.com. Tested on BillionMail 4.9.0 installed through aaPanel.