Mashup

A mashup is a web page or web application that combines content, data, or functionality from two or more external sources to create a single new service presented in a unified interface.

The term is borrowed from music, where it describes a track created by blending elements from existing recordings. In software, it implies quick, lightweight integration — typically using open [APIs] and publicly available data sources — rather than a formal systems integration effort.

A classic example of a mashup is overlaying a set of data points (library branch locations, crime statistics, real estate listings) onto an embedded map, combining the application’s own data with a third-party mapping service to produce something neither source could offer alone.

Mashups became prominent during the Web 2.0 era of the mid-2000s, when the proliferation of open APIs made it straightforward to pull data and functionality from services such as Google Maps, Flickr, and Twitter into third-party applications.

One of the earliest and most influential examples was HousingMaps.com (2005), which combined Craigslist rental listings with Google Maps before Google had offered any official mapping API — demonstrating both the creative potential and the unofficial, informal nature that characterized early mashup culture.

The concept helped establish the idea of the [API economy] – that exposing data and services programmatically creates value not just for direct users, but for the wider ecosystem of developers who build on top of them.