Email Marketing, Deliverability, and SMTP: What They Are and When You Need Each
Updated April 2026
Email software is not one market. Some tools help you grow and monetise an audience. Others help you stay out of spam. Others handle the sending infrastructure. Knowing which layer you actually need saves you from buying the wrong product.
In this guide
Email Marketing: Audience Growth and Monetisation
Email marketing platforms like Kit are built for creators and businesses growing an audience, sending newsletters, and monetising through subscriptions or products. If you need to write, automate, and send campaigns, this is the layer to start with.
Deliverability: Getting Into the Inbox
If emails are not landing in the inbox despite being well-written and well-targeted, the problem may be sender reputation. Tools like InboxAlly address this specifically — they are a stack layer that improves inbox placement, not a campaign builder.
SMTP Infrastructure: The Sending Engine
SMTP services like SMTP2GO handle the technical sending infrastructure. Apps, websites, and businesses use them to ensure emails reliably leave the system and reach recipients. This is a different job from newsletter marketing or inbox placement repair.