# 5.2.2. APIs in the World Wide Web From a web development perspective, APIs are often a set of HTTP requests and the according HTTP responses, which are often encoded in the XML or JSON format. An alternative to HTTP-requests and -responses is the usage of WebSockets, which is an advanced technology that opens an interactive communication session between a server and a client and eliminates the need for polling the server permanently. Almost every large online service offers at least one API to developers, in order to make possible third-party applications that use functions or data from the original service. Examples for web APIs are: • Facebook’s Graph API: It allows reading and writing Facebook user’s data, if the user authorizes the third-party app to do so. • YouTube Data API: Integrate YouTube features into an application, e.g. upload a video, manage a playlist, etc. • Google Maps API: A lot of things are possible with the API of Google Maps, e.g. putting a map on a website, finding information about places, getting directions and converting GPS coordinates into street addresses. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.futuregold.us/ai-arbitrage-trade-system/5.-technical-details/5.2.-apis-of-cryptocurrency-exchanges/5.2.2.-apis-in-the-world-wide-web.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.