API
4 synonyms for API, grouped by meaning and by how common each one is.
Noun — An agreed set of rules that lets one piece of software ask another for information or actions — what you can request, how to phrase the request, and what you will get back.
Synonyms
Everyday swaps
Common words most readers know — safe in any writing.
Rare, literary or technical
Precise, but they will stand out — check the sense before using one.
application programming interface
endpoint set
programmatic interface
How to use API
The word patterns that sound natural to a native speaker.
public API
REST API
API key
call an API
API endpoint
rate-limited API
Take the article that matches the spoken form: "an API", because it is said "ay-pee-eye". Almost never spelled out in full outside documentation.
Etymology
An initialism of application programming interface.
Full origin of API →Frequently asked questions
What is the difference between an API and a website?
A website returns pages designed for a person to look at; an API returns data designed for another program to process, usually in a format such as JSON. The same company often runs both against the same underlying information.
What is an API key?
An API key is a string of characters identifying who is making a request, so the provider can recognise the caller, apply limits and, where relevant, bill for use. It is a credential, so it is treated like a password rather than shared publicly.
What is the difference between an API and an SDK?
An API is the set of rules for making requests. An SDK, or software development kit, is a bundle of ready-made code and tools in a particular programming language that makes those requests for you. You can use an API without an SDK, but not the other way round.
