The short answer
Start with a handful a day from each sending address, build up over about a month, and keep each address to a modest daily number. Send from domains that are separate from your main one, so your everyday email is never at risk.
Many experienced senders keep each mailbox to a few dozen cold emails a day, and add more mailboxes rather than pushing one harder. There is no official number; the right pace is the one that keeps your emails landing in inboxes.
Why sending a lot at once backfires
Inbox providers like Gmail and Outlook watch how new senders behave. A brand-new address that suddenly sends hundreds of emails to strangers looks like spam, whatever the emails say. The result is not a warning; it is quietly landing in spam folders, sometimes for weeks.
Complaints make it worse. If people mark your emails as spam, providers trust everything from that domain less. That is why short, specific emails to the right person, a few at a time, work better than large blasts in both replies and delivery.
Warming up a new domain
A new sending domain and mailbox need a track record before they can send at full pace. Warming up means starting with a small number of emails a day and increasing gradually over several weeks while replies and engagement build trust.
This is also why cold email should go out from separate domains, not your main business domain. If something goes wrong on a sending domain, your invoices, customer emails and everyday mail are unaffected.
What Google and Yahoo require
Since 2024, Gmail and Yahoo have required all senders to authenticate their email, and set stricter rules for anyone sending in bulk. Google's sender guidelines, for example, ask every sender to set up SPF or DKIM and to keep reported spam rates below 0.3%. Senders of more than 5,000 messages a day to Gmail addresses must also set up SPF, DKIM and DMARC and offer one-click unsubscribe.
A small business sending a few dozen emails a day is far from bulk volume, but the same practices apply: authenticated domains, honest content, an easy way to opt out, and low complaint rates.
Why quality matters more than volume
The number that matters is not emails sent; it is the number of right-fit businesses that hear from you each week with something relevant to them. Twenty well-chosen, well-written emails a day, every weekday, adds up to hundreds of real conversations started over a few months.
How DemandSwarm paces sending
DemandSwarm builds a private sending network for each customer, with its own domains, authentication and warm-up. A new network starts with a handful of emails a day and builds to full pace over about a month,. Every email goes to one person, and a business stops hearing from the swarm the moment anyone there replies or opts out.