The one-sentence version#
A dedicated IP is used only by your mail; a shared IP pool is used by many senders on the same platform. Dedicated IPs give control over reputation but require volume and warm-up; shared pools borrow the platform's reputation.
Why you should care#
Choosing wrong either exposes you to neighbors' behavior or leaves an IP too cold to build reputation.
The mental model#
Think of dedicated IP addresses as a contract between you and the mailbox providers receiving your mail. You publish or configure something they can check; they check it on every message; the result feeds their decision about where your message lands. Everything below is about making that check pass consistently.
Your first setup, step by step#
- Estimate steady daily volume; below roughly 50,000 per day, shared pools usually perform better.
- If dedicated, warm up over 4 to 6 weeks and keep volume consistent.
- Separate transactional and marketing onto different IPs or pools.
- Monitor SNDS and Postmaster Tools per IP.
Words you will see#
- Mailbox provider: Gmail, Microsoft, Yahoo, Apple, and the corporate gateways that decide where mail lands.
- Authentication: proof that a message is from who it says it is (SPF, DKIM, DMARC).
- Reputation: the provider's running score of your domain and IP.
- Placement: whether a message reaches the inbox, spam, or is rejected.
Common mistakes#
- Buying a dedicated IP for a small list and letting it go cold.
- One dedicated IP for everything, so a promo blast delays receipts.
Frequently asked questions#
Do I need a dedicated IP for good deliverability?
No. Domain reputation dominates. Dedicated IPs are for high-volume senders who want isolation.