# API

/ˌeɪˌpiˈaɪ/ (US) · CEFR B2 · Noun

Source: https://englishreference.com/word/api
Updated: 2026-10-01

## Definition

Stands for Application Programming Interface. A set of rules that lets two computer programs talk to each other. You use it when you want an app to pull data from another service, like showing a map on a website.

For teachers: Abbreviation for Application Programming Interface. A set of protocols and tools that allows different software applications to communicate and share data. It is ubiquitous in modern web development for integrating third-party services.

## Examples

- The new weather app uses an API to get live forecasts.
- The developers integrated a payment API into the website so customers could check out securely without leaving the page.
- By opening its API to third-party developers, the platform rapidly expanded its ecosystem, allowing independent creators to build custom tools that the original team had never envisioned.

## Usage notes

- Pronounced as an initialism (A-P-I); typically takes the definite article when referring to a specific service's interface.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.