Cold email from your own domain, with sending limits built in

Should you send cold email from your own domain?

When you send cold email from your own domain, the person reading it sees your real name and address, and replies land in a mailbox you control. Bounces and spam complaints can also count against your domain's reputation.

That cuts both ways. A careful sender builds a reputation that stays with them, and a careless week can damage the domain you may also use for invoices and customer email.

Many senders keep cold outreach on a separate domain so a problem is less likely to reach the main one. The trade-off is that a new domain has no history, which is why a ramp matters. FoxKnock works with either, because it connects mailboxes you already own.

Google's sender guidelines for sending to personal Gmail accounts set the baseline (read in October 2026):

• Every sender sets up SPF or DKIM.
• Senders of more than 5,000 messages a day also add DMARC and support one-click unsubscribe on marketing and subscribed messages.
• Keep the spam rate in Postmaster Tools below 0.10% and avoid ever reaching 0.30%.

A small team is far below the 5,000 threshold, but the spam-rate guidance applies at any size.

Send cold email from Google Workspace or another mailbox

FoxKnock connects mailboxes with an app password over SMTP and IMAP. IMAP is needed so replies, later bounce notices and complaint reports can sync. Passwords are stored encrypted.

There is no Sign in with Google or Microsoft button, because FoxKnock does not use OAuth for mailboxes.

Google Workspace

Connect a Google Workspace mailbox over SMTP and IMAP with an app password. Google notes that app passwords need 2-Step Verification and may not be offered on some work or school accounts, so check with your Workspace admin first.

Any SMTP and IMAP server

Any other mail server that offers SMTP and IMAP can be connected with a password in the same way.

Microsoft 365 is limited

Microsoft no longer accepts passwords (Basic authentication) for IMAP in Exchange Online and is retiring them for SMTP AUTH. FoxKnock does not offer Microsoft sign-in, so a Microsoft 365 mailbox may fail to connect or may not sync replies.

Microsoft's documentation says (read in October 2026):

• Basic authentication is disabled for IMAP in all Exchange Online tenants and cannot be re-enabled.
• Basic authentication for SMTP AUTH will be off by default for existing tenants from the end of December 2026 (admins can turn it back on) and unavailable by default for new tenants.

If you want to test one anyway, SMTP AUTH has to be enabled on the mailbox, and a spare mailbox is the safer place to try. Otherwise, use a Google Workspace mailbox or another SMTP and IMAP provider.

Check SPF, DKIM and DMARC before the first send

After you connect, FoxKnock checks the domain's SPF, DKIM, DMARC and MX records and explains each problem with the fix.

The DKIM check tries common selectors (google, selector1, selector2, default, k1 and s1), so a custom selector can show as missing even when it is set up. For what each record does, read SPF, DKIM and DMARC for cold email.

Cold email sending limits and guardrails

Every connected mailbox gets the same defaults. They are low on purpose, because your domain carries the reputation.

Both pause checks need at least 20 sends. Complaints come from feedback-loop reports, which not every provider sends, so for Gmail also watch Postmaster Tools yourself.

Provider limits are not a safe volume

Google Workspace lets a paid user account send up to 2,000 messages a day and says limits can change without notice (read in October 2026). That tells you when Google will block you, not how much cold email your domain can absorb. For more on volume, see how many cold emails to send per day.

How to send more

More volume comes from more mailboxes, not a higher cap. For example, a 3-person agency on Growth could connect 6 mailboxes across 2 domains and, at default caps, send up to 150 emails a day once the ramp finishes.

Staying at 3 mailboxes per domain means more domains: Growth's 15 mailboxes would take at least 5, for up to 375 emails a day at default caps. Both numbers are illustrations, not forecasts.

What happens before each email leaves

Each email clears this path:

1. It is approved. By default a person approves each email. Automatic approval is opt-in and has to be earned, as explained in approval-first outreach.
2. The quality gate passes. In AI-written drafts, a claim that no source supports blocks the draft. So do unresolved variables, over-long copy and links that do not come from your own material. Spam trigger words lower the score.
3. Suppression is checked twice, when the step is queued and again at the moment of sending, so an unsubscribe in between still wins.
4. The address is re-verified if its last check is older than 14 days.
5. The footer is complete. A postal address is required, and by default first emails to the EU, EEA, UK, Switzerland or an unknown country need a link to your privacy notice.
6. Timing is enforced: working hours, 90 seconds between sends and that day's limit on the ramp.

This path is for outreach emails. The booking-link reply in the AI inbox is a separate case: it is off by default, and once you switch it on it sends without a per-message approval.

Every email carries a one-click unsubscribe link and the headers defined in RFC 8058. Compliance stays with the sender, and FoxKnock's built-in GDPR tools help.

Cold email deliverability: what FoxKnock controls

Deliverability depends on list quality, content, authentication, volume and complaints, plus each provider's own decisions. FoxKnock works on the parts you control:

• Verified addresses
• A quality gate on copy
• Visible DNS problems
• Capped volume
• Fast suppression

It cannot see inside a recipient's spam filter, so it never promises placement.

How it compares with the usual ways to send

Sending by hand from Gmail or Outlook. No ramp or automatic pause is built in, and nothing checks a shared suppression list, so the provider's sending limit is usually the only guardrail.

High-volume sending tools. These are built to connect many mailboxes. Instantly's pricing page, for example, lists unlimited email accounts and unlimited email warmup on its outreach plans (checked October 17, 2026). Instantly's help center describes its warm-up as a pool of other users' accounts that send each other warm-up emails (checked October 17, 2026). FoxKnock has no warm-up network and caps each mailbox at 50 a day, so if you need thousands of sends a day, a volume tool is the better fit.

Vendor-run sending pools. Some AI outreach tools send from mailboxes the vendor runs. Explee, for example, says on its homepage FAQ that outreach goes out from its pool of pre-warmed inboxes, never from the customer's own mailbox or domain, and that replies land inside Explee (checked October 17, 2026).

A vendor-run pool has real advantages: nothing to set up, and a mistake does not touch your own domain. The trade-off is that the mail does not come from your own domain. FoxKnock vs Explee compares the two with sources.

What it costs

The send itself uses no credits at default credit prices. Credits go on the work around it:

• An AI-personalized draft is 20 credits (templates you write yourself are free).
• Re-checking a contact whose last verification is older than 14 days is 1 credit.

Credit prices can change, so see pricing for the current table.

What the plan sets for sending is the number of mailboxes:

• Free: 1 mailbox
• Starter, $49/month: 3 mailboxes
• Growth, $149/month: 15 mailboxes
• Agency, $399/month: unlimited mailboxes

To see how it works on your own market, start free and use the 500 one-time credits on a small test: by default, nothing sends until you approve it.