Foundations are things you can “see,” such as buttons and panels. Buttons can trigger workflows, and panels embed information from somewhere else on the web.
Readers do just that — read data or “scrape” a webpage. Readers can extract data from a page's HTML or read data directly from the most popular web frameworks.
Effects take an input and perform an action. Effects range from opening a new tab, to inputting text into a search bar, to appending a row to a spreadsheet.
Transforms take an input and produce an output. Examples of this include calling an API, running a JSON transform, and parsing text.
Renderers show information on a page as an interactive web component or static HTML. Examples include rendering Markdown, or showing data in a table.
Services are reusable resources and configurations, such as a Google Sheet or Slack channel you can securely share. They can also be used to authenticate requests to service APIs.