Warming up your domain

A brand-new sending domain has no reputation. Mailbox providers — Gmail, Outlook, the big EU hosts — decide where your mail lands based on how recipients react to it, and at the start they have nothing to go on. “Warming up” is the process of starting small and ramping volume gradually, sending to people who actually want your mail, so providers learn to trust you before you're sending at full volume. Rush it and you train them to send you to spam. Do it right and you earn the inbox.

Who warms what

There are two reputations in play, and they warm separately. We handle the infrastructure side; you handle your domain. This is the same shared-responsibility model every serious sender uses.

Because we manage the IPs, you skip the hardest, slowest part of warming. Your job is to build your domain'sreputation — and that's mostly about who you send to and how fast you grow.

Before you send: authenticate your domain

Authentication isn't warming, but warming a domain that fails auth is wasted effort — providers distrust it from the first message. Get these in place first. The Domains page gives you the exact records; the docs explain each one.

• SPF & DKIM— add the DNS records we generate when you verify your domain. DKIM is how providers tie a message back to you; without it there's no domain reputation to build.
• DMARC — start with p=none so you can watch reports without affecting delivery. Once your legitimate mail is passing cleanly, tighten to quarantine, then reject. A published DMARC policy is increasingly a requirement, not a nicety.
• Use a subdomain — send from something like mail.yourdomain.comrather than your root domain. It isolates your sending reputation from the rest of your domain's use.

The ramp

Start with a small volume of your most engaged recipients and roughly double every few days, watching your numbers before each step up. The exact pace depends on your total volume and how engaged your list is — treat this as a shape, not a contract. If bounces or complaints climb, hold at the current level until they settle before ramping again.

The schedule above is a target for warming your domain; your plan also sets a daily ceiling, and whichever is lower applies. The Free plan is held at a low fixed daily rate. Paid accounts start with a conservative ceiling that lifts automatically over your first week of clean sending — no ticket, no waiting on us — and a clean reputation is what unlocks it, so a sudden jump in bounces or complaints pulls the ceiling back down. Your part is to feed it good traffic.

Send to people who want it

This is the part that actually decides whether warming works. Reputation is built on engagement — opens, clicks, replies — and destroyed by complaints and bounces. During warming especially:

• Start with your warmest contacts. People who signed up recently or interact with your product open your mail. Early opens are exactly the signal providers are looking for.
• Never send to a purchased or scraped list. It is the fastest way to tank a new domain — high bounces, spam-trap hits, complaints. One bad campaign during warming can undo weeks of work.
• Use real opt-in. Double opt-in for marketing mail keeps your list clean and your complaint rate near zero.
• Prune as you go.Remove hard bounces immediately and stop mailing contacts who haven't engaged in months. We suppress hard bounces and complaints automatically, but a list you keep tidy warms faster.

Watch these numbers

Your analytics dashboard shows delivery, opens, clicks, bounces, and complaints in real time. Before every step up in volume, check that you're inside these bounds:

These thresholds are deliberately strict — they're the same ones that protect every sender on the platform, and they only start to bite once you have enough volume to measure. If a number heads the wrong way, the fix is almost always the same: hold volume, tighten who you send to, and let things recover before growing again. A halved ceiling restores itself once your rates come back down.