Domain warmup

What warming up is

A new sending domain has no history. Mailbox providers respond to that by being cautious: they throttle it, route it to spam, or both. Warmup is the process of sending steadily growing volumes of mail that people actually engage with, so the domain builds a track record before you rely on it.

What a sane ramp looks like

There is no fixed schedule, and anyone quoting an exact one is overselling it. The shape that works is consistent:

• Start with a handful of messages a day per mailbox, to recipients likely to reply.
• Increase gradually over a few weeks, not in jumps.
• Keep volume steady once you reach it. Pausing for days and resuming at full speed looks like a hijacked account.
• Keep bounce rate near zero throughout. A new domain has no room to absorb bad data.

What warmup does not fix

• A dirty list. Warming the domain and then mailing unverified addresses undoes the effort in a day. Verify first.
• Missing authentication. Set up SPF, DKIM and DMARC before the first message. See the setup pages.
• Poor targeting. If people mark your mail as spam, no ramp compensates.

Use a separate domain

Send cold mail from a secondary domain, not your primary one, so that a reputation problem does not reach your customers' invoices. See primary domain and secondary domain, and the full warmup guide.