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Deliverability Letter

Internet Service Provider

Also known as: ISP

Companies that provide internet access and often email services to people and businesses. In email marketing, they decide if your emails reach the inbox or land in spam.

An Internet Service Provider is the company that gives people access to the internet. Often it also runs email services, like the inboxes people use every day. Examples include big consumer providers and business email hosts. When people talk about ISPs in email marketing, they usually mean the services that receive and filter your emails.

ISPs matter because every email you send has to pass through their filters. They look at your sending history, how people react to your emails, and how clean your list is. If they see too many complaints or bounces, they start to push more of your messages into the spam folder. Good sending habits help you earn trust and more inbox placement over time.

A simple way to keep ISPs happy is to focus on engaged subscribers. Send more often to people who open and click and less often to those who ignore you. Remove inactive and invalid addresses on a regular schedule. This keeps your reputation strong and makes it easier for future campaigns to reach the inbox.