A plans page outlining each of the access tiers for an API, provides a one-stop for business and technical API consumers to learn about how to onboard with an API, what features they get, the rate limits in place, and any pricing associated with API access. Plans provide the business side of what is needed to onboard with an API, but also maps that to authentication, rate limits, and other more technical aspects of using an API.
While a plans page provides what API consumers need, it also reflects how much planning an API producer has put into API. Plans can be adjusted over time, but provide a scaffolding to define how APIs are put to work in applications, securing digital resources and capabilities, but walking a line where you also want to make easy to access for the right consumers. Plan pages are usually provided by your API management provider, but can also be driven using your CMS, other approach to managing internal or external API doorways.