A shared IP sends your email from an address used by many customers of the same provider, so reputation is pooled. A dedicated IP is used only by you, so reputation is entirely your own. Dedicated IPs suit large, steady senders. Shared IPs suit most small and mid-sized senders.
How does a shared IP work?
Your provider sends mail for many customers from a pool of IPs and manages the pool's reputation by enforcing rules on all customers. Good providers remove abusive senders quickly.
The upsides are that the IPs are already warm and you need no ramp-up. The downside is that another customer's bad behavior can affect you, and you have limited control.
How does a dedicated IP work?
The IP is yours, so your results depend only on your own practices. You control reputation, can separate streams across IPs, and can be sure that nobody else is hurting you.
The cost is responsibility. A new dedicated IP has no reputation and must be warmed up, as covered in the warm-up guide. It also needs steady volume, because very low or irregular sending makes it hard to build a reputation.
Which one should you choose?
- Choose shared if you send low or irregular volume, you are just starting, or you do not have someone to manage reputation.
- Choose dedicated if your volume is high and consistent, you need to isolate streams such as marketing and transactional, or you have been affected by neighbors on a shared pool.
- Consider a provider with sensible shared pools if you are unsure. You can move to dedicated later.
Neither option fixes bad practices. A dedicated IP with a dirty list will build a bad reputation faster, not slower.
What else matters about infrastructure?
Whatever IP type you use, you need reverse DNS that resolves to a hostname, TLS enabled and aligned authentication. Check your DNS records and the baseline in the Gmail and Yahoo requirements. If you use your own SMTP server rather than a platform, see free SMTP servers and Gmail SMTP for options and limits.
When does an expert help?
IP strategy is one of the topics where a specialist saves time. See when to hire a deliverability consultant and compare deliverability services.
Frequently asked questions
Do I need a dedicated IP for good deliverability?
No. Many senders get excellent results on shared pools from reputable providers. Dedicated IPs matter mainly at high, steady volumes.
How much volume does a dedicated IP need?
Providers give different guidance. As a general principle you need consistent sending so that mailbox providers can learn your pattern. Ask your provider for its recommendation.
Can I switch from shared to dedicated later?
Yes. Plan a warm-up and move volume gradually while keeping the old setup in place.
Does the IP matter more than the domain?
Both matter. Domain reputation is increasingly important, especially at Gmail, and it follows you across IPs.