Email Warm-Up and Dedicated vs Shared IP: Which Do You Need?

Most businesses should send from a shared IP pool and not pay for a dedicated IP. A dedicated IP only helps when you send large, regular volumes, because mailbox providers need steady traffic from an address before they trust it; Amazon SES recommends shared IPs unless you send large volumes on a regular and predictable basis, and SendGrid suggests at least two dedicated IPs once you reach 250,000 messages a month. Whichever you use, a new IP or a new domain needs warming up: start with small volumes to your most engaged recipients and increase gradually over several weeks.

This guide is for founders, marketers and developers choosing how their app, shop or newsletter sends mail, or planning a move to a new sending service or domain. It explains the trade-offs, gives warm-up numbers only from the providers' own documentation, and covers warming a domain, which matters even on shared IPs.

#Shared and dedicated IPs in plain words

Every email is delivered from an IP address, and mailbox providers keep a reputation for each address. The question is whether you share that address with other customers of your sending service.

Shared IP. Your mail goes out from a pool of addresses used by many senders. Google's sender guidelines put it plainly: the activity of any sender on a shared IP affects the reputation of all senders on it. Good providers manage this actively. Amazon SES says AWS carefully manages outbound traffic on its shared IPs to protect their reputation.

Dedicated IP. The address is used only by you. Your sending habits alone decide its reputation, which is good if you send well and steadily, and bad if you do not.

Your domain has its own reputation too, separate from the IP. Moving to a dedicated IP does not fix a poor domain reputation, and a good domain reputation does not survive bad sending on any IP.

#Dedicated vs shared IP compared

Some details from the providers' own pages, at the time of writing (November 2026):

• Amazon SES lists standard dedicated IPs at $24.95 per IP per month, and managed dedicated IPs at $15 per account per month plus a per-email fee that starts at $0.08 per 1,000 emails. Check the SES pricing page (opens in a new tab) for current rates.
• Amazon SES says most providers only track an IP's reputation once they receive significant volume from it, and suggests sending several hundred emails within 24 hours at least once a month to each provider you want a reputation with.
• SendGrid sends Trial and Essentials accounts from shared pools, includes one dedicated IP with its Pro Email API and Advanced Marketing Campaigns plans, and charges monthly for each extra IP. It suggests one dedicated IP for every three to four million messages a day.

#When a dedicated IP makes sense

A dedicated IP is worth it when all of these are true:

1. You send large volumes every week, not one big campaign a quarter. Amazon SES says shared IPs are best for low-volume senders and recommends shared IPs if you do not send large volumes regularly and predictably.
2. Your list is clean and your complaint rate is low. A dedicated IP exposes your own practices. If they are weak, you lose the cover of a well-run pool.
3. You want to separate streams, for example keeping order confirmations away from marketing campaigns, so a bad campaign cannot delay receipts. SendGrid suggests a minimum of two dedicated IPs, one for marketing and one for transactional mail, once you reach 250,000 messages a month.
4. Someone needs fixed IP addresses, such as a business customer whose mail server only accepts listed IPs. Amazon SES notes this case can justify a dedicated IP even at small volume.

If your sending is irregular but you still want isolation, Amazon SES offers managed dedicated IPs, which warm up per mailbox provider automatically and scale with your volume. For most small and mid-sized businesses, the right move is a reputable sending service on its shared pool, with your own domain fully authenticated. Transactional email and SMTP setup covers choosing and connecting one.

#How IP warm-up works

Warm-up means increasing volume on a new IP gradually, so mailbox providers see a steady, well-received history instead of a sudden flood from an unknown address. There is no universal schedule; the right numbers come from your provider.

What the two big providers publish:

Both providers give the same practical advice. Amazon SES says to send to your most active users first so complaints stay low, to watch bounce messages, and to send less if you see blocking or throttling. SendGrid notes that for transactional mail you cannot control when emails trigger, so a strict schedule matters less, and that a slow warm-up for marketing mail helps you catch problems early.

During warm-up:

• Send your most engaged segment first, such as people who opened or bought recently.
• Keep transactional mail, such as receipts and password resets, on a warm IP or shared pool where possible.
• Watch bounces, deferrals and complaints daily. Pause and reduce volume at the first sign of blocking.
• Do not import an old list during warm-up. Old addresses bounce and drag the new IP down.

#Warming a new domain

A brand new domain has no history, and providers are cautious with it whatever IP it sends from. Google's guidance is the same for domains as for IPs: start with a low volume to engaged users, increase slowly, and avoid sudden volume spikes if you have no history of sending large volumes.

Before the first send, make sure the domain is ready:

1. SPF, DKIM and DMARC published and passing for every service that will send. See SPF, DKIM and DMARC setup.
2. A website on the domain and a monitored reply address, so the domain looks like a real business.
3. Consistent From addresses per mail type, as Google suggests.
4. Google Postmaster Tools set up to watch spam rate once volume builds.

Many businesses keep newsletters on a subdomain such as news.yourdomain.com. Microsoft recommends using a subdomain for bulk email services you do not control, so problems with that mail do not affect the reputation of your main domain. A subdomain still needs warming like any new sender.

#When to get help

If you send a few thousand emails a month through a reputable service on its shared pool, you do not need a dedicated IP or a warm-up plan beyond sending steadily to people who opted in. Get help when you are moving a large list to a new provider, launching a new domain for marketing, considering dedicated IPs, or seeing bounces and deferrals during a warm-up. A rushed migration can undo years of good reputation in a week.

My email deliverability service covers planning the move, authentication, warm-up monitoring and DMARC reporting. If your messages are already in spam, read why your emails go to spam first, and check the Gmail, Yahoo and Microsoft sender requirements your new setup must meet.