There are three primary ways to work with third-party services in Ghost: using Zapier, editing your theme, or using the Ghost API.
You can connect your Ghost site to over 1,000 external services using the official integration with Zapier.
Zapier sets up automations with Triggers and Actions, which allows you to create and customise a wide range of connected applications.
Example: When someone new subscribes to a newsletter on a Ghost site (Trigger) then the contact information is automatically pushed into MailChimp (Action).
Here are the most popular Ghost<>Zapier automation templates:
Editing your theme
Ghost comes with a beautiful default theme called Casper, which is designed to be a clean, readable publication layout and can be adapted for most purposes. However, Ghost can also be completely themed to suit your needs. Rather than just giving you a few basic settings which act as a poor proxy for code, we just let you write code.
There are a huge range of both free and premium pre-built themes which you can get from the Ghost Theme Marketplace, or you can create your own from scratch.