Our mail platforms have sending limits that protect the reputation of your domain and of our servers. The limits depend on where your mailbox is: StackCP and Business Email, or cPanel hosting.
StackCP and Business Email
Sending through SMTP
These limits apply to email you send through authenticated SMTP, for example from Outlook, your phone, or a website that sends through a real mailbox.
| Limit | Value |
|---|---|
| Messages per email address | Up to 8,000 in 24 hours |
| Total recipients | Up to 10,000 per day |
| Unique recipients | Up to 2,000 per day |
| Recipients in one message | Up to 100 |
Example: you send 100 messages in 24 hours, and each one goes to the same 5 addresses. That counts as 100 messages, 500 recipients and 5 unique recipients.
New mailboxes
A new mailbox can send up to 50 messages per day for the first 7 days. After that, the normal limits apply.
Sending from your website (PHP mail)
| Limit | Value |
|---|---|
Email sent by the web server (for example PHP mail()) | Up to 500 messages per day |
| Size of one message sent by the web server | Up to 5 MB |
We recommend sending website email (contact forms, WooCommerce orders) through SMTP with a real mailbox, for example with an SMTP plugin in WordPress. It is more reliable and lands in spam less often.
Message size and autoresponders
| Limit | Value |
|---|---|
| Attachment | Up to 32 MB |
| Whole message | Up to 50 MB |
| Autoresponder | One automatic reply per sender every 8 hours |
cPanel hosting
On standard cPanel hosting, each cPanel account can send up to 100 messages per hour. The limit counts all mailboxes and scripts in the account together.
Rules for both platforms
- We have zero tolerance for spam and unsolicited bulk email. Accounts that break this rule can be suspended or terminated.
- Newsletters and marketing campaigns must go through a specialised email service, for example Mailchimp, SendGrid, Mailgun or Mailjet.
- Because our mail network is distributed, you may sometimes be able to send a little more than the limits above. Do not rely on this. Plan your sending within the limits.
Important — using Cloudflare? Your domain can stay on Cloudflare. In your mail app, connect directly to the mail servers: imap.stackmail.com and smtp.stackmail.com for StackCP and Business Email, or your server hostname for cPanel (see Email Accounts > Connect Devices in cPanel). Do not use mail.yourdomain.com while the domain is behind the Cloudflare proxy. In Cloudflare DNS, set all mail records (the MX target, mail, imap, smtp, pop3, webmail and similar) to DNS only (grey cloud). Email does not work through the proxy (orange cloud).