posta

Mailbox API: create real IMAP and SMTP mailboxes on your own domain from code.

posta is open-source email hosting with an API, built for developers and AI agents. Connect a domain you own, verify the DNS records, then create mailboxes with one API call or from a small web panel. Each mailbox is a real IMAP/SMTP mailbox. It is not a forwarding rule and not a sending-only API.

Hosted free early access: https://posta.preved.co (1 domain, 1 mailbox, 500 MB, 50 outgoing messages a day, no card).

What you get

• Domain ownership and DNS verification (ownership TXT, MX, SPF, DKIM, DMARC)
• Mailboxes over IMAP (993) and SMTP (587 and 465), your own domain, TLS
• REST API with bearer keys: /v1/me, /v1/domains, /v1/mailboxes, /v1/usage
• Web panel for sign-up, domains, mailboxes and API keys
• Per-mailbox size and daily sending limits
• Audit log, and a backend interface: mailcow for real mailboxes, dryrun for development

How it works

customer ──HTTPS──▶ posta (Django: panel + API) ──API──▶ Mailcow (Postfix, Dovecot, Rspamd)
mail client ───────IMAP 993 / SMTP 587, 465────────────▶ Mailcow

posta manages domains and mailboxes. Mailcow runs the mail.

Quick start (development)

git clone https://github.com/bexx2/posta.git && cd posta
python -m venv .venv && . .venv/bin/activate
pip install -r requirements.txt
cp .env.example .env        # keep MAIL_BACKEND=dryrun, set DB_* for PostgreSQL
cd app && python manage.py migrate && python manage.py runserver

For real mailboxes set MAIL_BACKEND=mailcow and give posta a Mailcow API key.

API example

curl -s https://posta.preved.co/v1/mailboxes \
  -H "Authorization: Bearer $POSTA_KEY" \
  -H "Content-Type: application/json" \
  -d '{"domain":"acme.dev","local":"agent"}'

Full API reference is coming. Until then the endpoints above are stable.

Who it is for

Developers shipping a new product, agencies setting up client domains, and people building AI agents that need their own email address.

Project status

Early access. Outgoing mail to Outlook and Hotmail may be rejected for now. Bulk and marketing email is not allowed on the hosted service.

License

AGPL-3.0. You can read, run and modify posta. If you offer a modified version as a service, you must publish your changes under the same license. The name "posta" and its logo are not covered by the license.

Operated by HEYVANKA YAZILIM LTD. ŞTİ., Türkiye.