What’s the difference between shared vs dedicated SMTPs?

The choice between shared and dedicated SMTP infrastructure affects how reputation is built and attributed.

Shared SMTP:

Multiple senders use the same IP pool

Pool reputation is collective (others' behavior affects you)

Lower volume requirements since reputation is distributed

Quality depends on provider's sender vetting and enforcement

Common for cold email tools and smaller senders

Dedicated SMTP:

You're the only sender on your IP addresses

Reputation is entirely yours to build and maintain

Requires sufficient volume to establish reputation

Higher cost and management overhead

Better visibility into what affects deliverability

For cold email: Most cold senders lack volume for dedicated infrastructure. Domain reputation matters more than IP reputation for modern filtering anyway. If using shared infrastructure, choose providers with strict sender policies and good pool hygiene.

The infrastructure choice matters less than how you use it. A well-maintained shared vessel can outperform a neglected private yacht.