MailHub

Built for production senders

Everything you need to authenticate domains and observe delivery.

Domains & DNS

Guided SPF, DKIM, DMARC, and one-click DNS provider writes.

SMTP Submission

App-friendly SMTP listeners with credentials you control.

HTTP Send API

Bearer tokens and a simple JSON send endpoint for apps and services.

Mailboxes & receiving

Create persistent or expiring inboxes with IMAP, POP3, forwarding, and catch-all routing.

Delivery logs

Track queue and MTA outcomes with searchable send history.

Webhooks

Signed callbacks for sent, bounced, and failed terminal events.

Multi-user isolation

Domains, tokens, and logs stay scoped to each account.

Start in four steps

The console keeps domain, token, mailbox, and delivery configuration in one place.

1

Add a domain

Add your sending domain and publish the DNS records shown by MailHub.

Review domain setup →

2

Create a scoped token

Give each integration only the send or mailbox permissions it needs.

Review API access →

3

Provision mailboxes

Create persistent mailboxes in the console or create persistent and temporary mailboxes by API.

Review mailbox API →

4

Connect your client

Use SMTP to send and IMAP or POP3 to receive with the mailbox's full address and password.

Review protocol settings →

API authentication and sending

All public API calls use a Bearer token. The hostname below is a placeholder; replace it with your MailHub host.

Create and protect a token

Create a token in Console > API Tokens. The complete secret is shown only once, so store it outside browser code and public repositories.

send — send messages with POST /api/send
mailboxes:read — list mailboxes with GET /api/mailboxes
mailboxes:write — create mailboxes with POST /api/mailboxes

Send a message

The From domain must belong to the token account. When verified sending is enabled, complete the domain DNS checks before sending.

Authorization: Bearer <USER_API_TOKEN>

POST /api/send

Field	Required	Description
`from`	Yes	sender address on an account-owned domain
`to`	Yes	recipient string or an address array
`subject`	No	defaults to (no subject)
`text`	No	plain-text body
`html`	No	HTML body; required when enabling open or click tracking
`tracking`	No	true/false, or { opens, clicks }; rewrites HTML only
`smtpRelayId`	No	an account-owned outbound SMTP relay ID

202 response

A 202 response means MailHub accepted the message for SMTP delivery. Use the console delivery log or webhooks to observe the later result.

Mailbox API and clients

Create a persistent address for ongoing work, or an expiring address for a short-lived workflow.

Mailbox API scope

POST /api/mailboxes requires mailboxes:write. The target domain must belong to the token account.

mode — permanent or temporary
address / domain — use a full address, or choose domain plus localPart
expiresInMinutes — required for temporary mailboxes; 5 minutes to 30 days
password — optional; a secure password is returned once when omitted

Use the returned configuration

Creation returns the address, password, expiration, and ready-to-use IMAP, POP3, and SMTP settings.

IMAP — recommended for synchronized folders and sent mail
POP3 — for download-oriented clients
SMTP — use the same full mailbox address and password to send

POST /api/mailboxes - permanent

POST /api/mailboxes - temporary

GET /api/mailboxes

201 creation response

The returned password is the only opportunity to read an automatically generated password.
A temporary mailbox expires after the requested interval and then stops receiving mail and authenticating.
Use mailboxes:read to list mailbox metadata; passwords are never returned by the list endpoint.

Receiving mail

Mail arrives through the domain MX record. Read it in MailHub Inbox or through standard IMAP/POP3 clients; there is no separate inbound Bearer API.

Inbound delivery

Set the domain MX record to the receiving host. External mail servers then deliver to SMTP port 25, and MailHub stores mail for an existing mailbox, alias, or catch-all target.

Mailbox, aliases, and catch-all

Create a full mailbox address first. Add aliases or forwarding on that mailbox, and configure the domain catch-all in the console to route unknown local parts to a mailbox or another address.

Protocol	Recommended ports	Security	Use
IMAP	`993` / `143`	SSL/TLS or STARTTLS	recommended for synchronized folders
POP3	`995` / `110`	SSL/TLS or STLS	download-oriented clients
SMTP	`465` / `587`	SMTPS or STARTTLS	send with the same mailbox address and password

IMAP exposes INBOX, Sent, Drafts, Trash, Junk, and Archive. Use IMAP when the client should synchronize these folders and save sent messages.

Domain configuration

Create the domain in MailHub first. Its DNS panel is the source of truth for your exact verification, DKIM, SPF, DMARC, and sender-host values.

Purpose	Record	Requirement
Domain ownership	`TXT _mailhub.<domain>`	Publish the verification value generated in the console.
DKIM	`TXT <selector>._domainkey.<domain>`	Publish the public key generated for this domain.
SPF	`TXT <domain>`	Keep one SPF record and include the sender IP/host required by MailHub.
DMARC	`TXT _dmarc.<domain>`	Start with monitoring, then strengthen the policy after alignment is verified.
Inbound mail	`MX <domain>`	Point MX to the MailHub receiving host and ensure that host has an A/AAAA record.

For reliable delivery, also configure the sending IP's PTR to match the MailHub sending hostname and allow the documented SMTP, IMAP, and POP3 ports through your firewall.

SMTP submission

Default listener ports (override in your deployment):

25smtp

587smtp / STARTTLS

465smtps

2525smtp

Application SMTP

Create an SMTP login credential in the console for an application. Use that credential with an account-owned From domain.

Mailbox SMTP

A created mailbox can also authenticate over SMTP with its full email address and password. Use the same credentials for IMAP or POP3.

Prefer 465 or 587 for sending, 993 for IMAP, and 995 for POP3. The creation response is the source of truth when a deployment overrides default ports or TLS listeners.

Responses and common errors

The API returns JSON. Validate the HTTP status before consuming a response body.

Status	Meaning	What to do
`201`	Mailbox created	Store the one-time password and clientConfig.
`202`	Message accepted for SMTP delivery	Inspect delivery logs or webhooks for later delivery status.
`400`	Invalid request or domain ownership rule	Read the JSON error and correct the request body or domain setup.
`401`	Missing, invalid, revoked, or expired token	Create or rotate a valid token.
`403`	Token does not have the required scope	Grant the minimum required scope in Console > API Tokens.
`409`	Mailbox address already exists	Choose another address or use the existing mailbox.

Delivery webhooks

Terminal events only — signed HTTPS callbacks to your systems.

Status	type
`sent`	`email.sent`
`bounced`	`email.bounced`
`failed`	`email.failed`

Signature header: X-MailHub-Signature: t=<unix>,v1=<hmac>

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Send reliable email via API & SMTP