API (Application Programming Interface)
Definition
A standardized set of protocols enabling different software systems to exchange data and functionality without exposing their internal implementation details.
An API serves as a contract between software systems, defining how they can request and exchange information. Just as a restaurant menu tells you what you can order without revealing kitchen operations, an API tells developers what requests they can make and what responses to expect, abstracting away the complexity of the underlying system.
Modern APIs primarily use REST architecture with HTTP methods, returning data in JSON format. A developer might call a payment API to process a credit card charge, a maps API to embed directions, or a weather API to display forecasts. Each call includes an endpoint URL, authentication credentials, and any required parameters.
API economy has transformed how software is built. Instead of coding every feature from scratch, developers compose applications by integrating best-in-class APIs for payments, authentication, messaging, analytics, and more. Rate limiting, versioning, and comprehensive documentation are hallmarks of well-designed APIs that developers trust and adopt at scale.
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Related Terms
REST API
techAn architectural style for web services that uses standard HTTP methods to create, read, update, and delete resources, providing a stateless communication interface.
JSON (JavaScript Object Notation)
techA lightweight data interchange format that is easy for humans to read and write and easy for machines to parse and generate.
HTTP (HyperText Transfer Protocol)
techThe foundational protocol for data communication on the web, defining how messages are formatted and transmitted between clients and servers.
JWT (JSON Web Token)
techA compact, self-contained token format used for securely transmitting claims between parties as a digitally signed JSON object for authentication.
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