Guide
How to warm up a new email domain.
Why a new sending domain needs a warm-up, how long it takes, who to send to first, and the Gmail and Yahoo rules to meet before your first campaign.
Updated · 4 min read
The short answer
Start small, send to the people most likely to open, and raise your daily volume only as fast as your results allow. A common pattern is to start at a few hundred emails a day and double after each clean day, so a domain can reach 10,000 a day in about a week. How long yours takes depends on your list size and your bounce and complaint rates, not the calendar. Before your first send, set up SPF, DKIM and DMARC and one-click unsubscribe, and keep spam complaints well under Gmail’s and Yahoo’s 0.3% line.
Why a new domain needs a warm-up
Gmail, Yahoo and the other mailbox providers decide where your email lands partly on your sending history. A new domain, or a new email platform sending for an old one, has none. A sudden burst of email from an unknown sender is what spam looks like, so the first big send from a cold domain often lands in spam or gets throttled. A warm-up builds that history gradually, with the people most likely to welcome your mail.
Before the first send
Gmail’s and Yahoo’s rules for bulk senders (Gmail counts anyone sending close to 5,000 messages a day to its users) are the baseline every store should meet anyway (Google: email sender guidelines, Yahoo: sender best practices):
- Authenticate your domain with SPF and DKIM, and publish a DMARC policy.
- Offer one-click unsubscribe in the email headers, plus a visible unsubscribe link, and honor it within two days.
- Keep spam complaints low. Gmail asks senders to stay under 0.1% and never reach 0.3%. Yahoo’s line is also 0.3%.
- Send only to people who asked for your email.
Who to send to first
Start with the people most likely to open and click: customers who opened or clicked in the last 90 to 120 days, recent buyers and new signups. Leave the rest of the list until your limit can carry it. Clicks and orders are better signals than opens, because some mail apps open email on the reader’s behalf.
How fast to grow
Grow from what you actually sent, not from a schedule. A day with high delivery and low bounces and complaints earns a bigger limit tomorrow. A day that dips should grow slowly or not at all, and rising bounces or complaints should stop marketing sends until they recover.
| Day | Daily limit |
|---|---|
| Day 1 | 200 emails |
| Day 2 | 400 emails |
| Day 3 | 800 emails |
| Day 4 | 1,600 emails |
| Day 5 | 3,200 emails |
| Day 6 | 6,400 emails |
| Day 7 | 12,800 emails |
Past about 10,000 a day, most ramps grow more cautiously, by about half a day, unless the results are excellent.
How long a warm-up takes
For a list of a few thousand, often under a week. For tens of thousands, a week or two. For a very large list, longer. The deciding factors are how close you can send to your limit each day and how clean the results are: a day you don’t send teaches the mailbox providers nothing, and a day with complaints slows everything down.
Sending a big campaign during the warm-up
If a campaign’s audience is bigger than today’s limit, don’t blast it. Send it in batches across several days, most engaged people first, so each day’s send stays inside the limit and keeps growing it.
How Amy warms up your domain
- Amy sets up DKIM and SPF on your own domain and leaves your existing DNS alone.
- A new domain starts small and grows from what actually went out: good results raise your daily limit, and great results double it.
- Your limit never drops below your best clean day.
- Marketing email pauses on its own if hard bounces pass 2%, or spam complaints pass 0.08% over the last 30 days, far inside the 0.3% Gmail and Yahoo enforce.
- A campaign bigger than today’s limit goes out over several days, most engaged customers first, and the composer tells you how many days before you send.
- Coming from Klaviyo, your first sends go to people who opened or clicked there in the last 120 days.
Sources: Google’s email sender guidelines and FAQ, and Yahoo’s sender best practices, read October 2026.
Questions
How long does it take to warm up an email domain?
For a list of a few thousand, often under a week. For tens of thousands, a week or two, and longer for very large lists. It depends on how close you send to your daily limit and how clean your bounce and complaint rates are.
How many emails should I send when warming up a domain?
Start with a few hundred a day to your most engaged contacts, then raise the limit after each clean day. Doubling from 200 a day reaches 12,800 a day on the seventh day if every day is clean.
Do I need to warm up my domain when I switch email platforms?
Yes. The new platform sends from servers mailbox providers haven’t seen sending for you, so start with engaged customers and grow from there.
What happens if I send too much from a new domain?
Mailbox providers may send it to spam, slow it down or reject it, and the damage to your domain’s reputation can take weeks to repair.
What spam complaint rate is too high?
Gmail asks senders to stay under 0.1% and never reach 0.3%, and Yahoo’s line is 0.3%. Amy pauses marketing email at 0.08% over the last 30 days.
Do I need SPF, DKIM and DMARC?
Yes. Gmail and Yahoo require SPF and DKIM for bulk senders, plus a published DMARC policy, and one-click unsubscribe on marketing email.
Does Amy warm up my domain automatically?
Yes. Amy sets up DKIM and SPF, grows your daily limit from what actually went out, never drops it below your best clean day, and pauses marketing on her own if bounces or complaints climb.