A plan is a collection of API resources or subsets of resources from one or more API. A plan can contain a mixture of HTTP, GET, PUT, POST and DELETE actions from different APIs or it can contain all the actions from various APIs. A plan can have a common rate limit for all the resources or each resource can have a different rate limit. Rate limits specify how many calls an app is allowed to make during a specified time interval.
Use the Developer Portal to browse the different plans that are available and select a plan that is more suitable for your requirements. Some plans are restricted and require you to request access before you can use them. When you submit your request, the organisation is notified, the API administrator assesses your request and they might contact you for more details. Other plans are available to use straight away.