Mailboxes on your own domain
EU-hosted email hosting with webmail included. Create mailboxes on your domain, let each person read and send at mail.poststack.dev, or connect any IMAP or POP3 client.
Webmail included
Everyone with a mailbox signs in at mail.poststack.dev with their address and password — no PostStack account, no app to install. Folders, search, attachments, and new mail the moment it arrives.
Standards-based hosting
Every mailbox is available over IMAP and POP3, with SMTP submission for sending. Connect Thunderbird, Apple Mail, Outlook, or any phone mail app with the same six settings: server, ports, and your full address as the username.
One provider for everything
Send through the API, receive in mailboxes, and manage in webmail, all on the same EU infrastructure with TLS enforced on every connection.
Create a mailbox
await poststack.mailboxes.create({
domainId: 42, // a verified domain on your account
localPart: 'support', // → support@yourdomain.com
password: 'a-long-random-password',
displayName: 'Support Team',
});Use cases
Customer support inbox
Create `support@yourdomain.com` and `help@yourdomain.com`. Replies route to the PostStack webmail, your team replies directly, and the threading stays intact in the customer’s inbox.
Founder and team personal mail
Run `michael@yourcompany.com` as a real IMAP mailbox while sending transactional email through the same PostStack account. Two products on one credential, one domain, one bill.
Inbound reply handling for newsletters
Configure the newsletter `Reply-To` to land in a real mailbox rather than vanishing into a webhook. Read and reply from webmail or any IMAP client.
Programmatic inbox processing
Combine mailboxes with inbound webhooks to fan email out to multiple downstream systems — store in your database, raise a support ticket, post to Slack, all triggered from a single received message.
How it works
PostStack mailboxes are real IMAP/POP3 mailboxes backed by Dovecot, running on the same EU infrastructure as the API. Create a mailbox under any verified domain and use it as a normal email account — IMAP on port 993 (TLS), POP3 on port 995 (TLS), SMTP submission on port 465 (implicit TLS) or 587 (STARTTLS or implicit TLS). Email clients like Thunderbird, Apple Mail, Outlook, and the built-in mail apps on iOS and Android connect directly.
Every client uses the same settings: the server name, those ports, and the full email address as the username. A Mozilla-format autoconfig document at `/.well-known/autoconfig/mail/config-v1.1.xml` is also available for Thunderbird.
Each mailbox’s own user signs in to webmail at mail.poststack.dev with the mailbox address and password, and the PostStack dashboard shows the same webmail to account admins: read, compose, reply, forward, attach, organise into folders, search, and use Gmail-style keyboard shortcuts (j/k to move, r reply, a reply-all, f forward, e archive, c compose). Conversations are threaded, and the webmail uses IMAP IDLE so new mail appears within seconds of arrival without polling.
Inbound messages are fully delivered to the mailbox — there is no API-only "inbound" mode that requires special webhook handling. Incoming mail is filtered by Rspamd, with DNS blocklist lookups, DKIM/SPF/DMARC verification, and Bayesian classification. Storage is per-mailbox quota: mailboxes are available on every paid plan at €1/mo each, including 1 GB of storage, and each can be expanded up to 50 GB at €1/GB/mo. Mailbox passwords are bcrypt-hashed and managed separately from the team password so a compromised webmail password does not expose your PostStack admin account.
Every parameter, limit, and example is in the documentation.
Frequently asked questions
Are these real IMAP mailboxes?
Yes — backed by Dovecot, accessible via IMAP, POP3, and SMTP submission. Connect Thunderbird, Apple Mail, Outlook, or your phone’s mail app. Every client uses the same few settings — server, ports, and the full address as the username — shown on the mailbox page.
Can I use my own domain?
Yes. Verify a domain for sending (SPF/DKIM/DMARC), then add a single MX record pointing at PostStack and you can create mailboxes on that domain.
How is spam filtered?
Incoming mail passes through Rspamd, with DNS blocklist (RBL) lookups, DKIM/SPF/DMARC verification, and Bayesian classification. Messages scored as spam are marked so your client or webmail can file them away from the inbox.
Is webmail included?
Yes. Each mailbox’s own user signs in at mail.poststack.dev with the mailbox address and password and sees only that mailbox. Compose, reply, search, folders, attachments, threading, and keyboard shortcuts — no email client required. They can also connect their old t-online, GMX, or WEB.DE address and read it in the same place.
Can I send from mailboxes?
Yes. Each mailbox supports outbound SMTP submission on port 465 (TLS). The same DKIM signing and deliverability machinery the API uses applies to mailbox sends.
What about quotas?
Mailboxes are a €1/mo add-on on any paid plan (not available on Free). Each includes 1 GB of storage and can be expanded up to 50 GB at €1 per extra GB per month. Mail sent to a mailbox that is already full is refused, so raise the quota before it fills.