Kit

What it is

Kit is an email marketing and audience management platform for creators and newsletter operators, available through the Kit developer portal. Its REST API, described in the Kit API overview, lets developers create and send broadcasts to subscribers, manage the list with tags and custom fields, and import purchase data. According to the Kit API authentication guide, the V4 API supports OAuth 2.0 and API keys.

When it fits

Kit suits creators and newsletter operators who send broadcasts and organize their audience with tags and segments. These are included in every plan, according to the Kit billing guide. Kit bills on confirmed subscribers, not on emails sent, so sending more often does not change the bill.

What to watch

Developers who integrate Kit into custom web apps need an authenticated account on a plan that allows API and app access, as the Kit API overview notes. According to the Kit email data retention policy, email stats are kept for a rolling five-year window. Stats for emails sent more than three years ago stop updating, and stats older than five years are archived and no longer returned by the API. Apps that need a longer engagement history should sync stats before they age out of the window.