It encompasses various types of fixed, mobile, and portable two way radios, cellular telephones, personal digital assistants (PDAs), and wireless networking. Other examples of wireless technology include GPS units, garage door openers and or garage doors, wireless computer mice, keyboards and headsets, satellite television and cordless telephones.

Wi-Fi (IPA: /?wa?fa?/) is a trademark of the Wi-Fi Alliance, founded in 1999 as Wireless Internet Compatibility Alliance (WICA), comprising more than 300 companies, whose products are certified by the Wi-Fi Alliance, based on the IEEE 802.11 standards (also called Wireless LAN (WLAN) and Wi-Fi). This certification warrants interoperability between different wireless devices.

The alliance was founded because many products did not correctly implement IEEE 802.11 and some included proprietary extensions. This led to incompatibilities between products from different manufacturers.

The Wi-Fi Alliance tests the wireless components to their own terms of reference. Products that pass become Wi-Fi certified and may carry the Wi-Fi logo. Only products of Wi-Fi Members are tested, because they pay membership and per-item fees. Absence of the Wi-Fi logo does not necessarily mean non-compliance with the standard.

In France, Poland, the United States, and some other countries, the term Wi-Fi often is used by the public as a synonym for wireless Internet (WLAN); but not every wireless Internet product has a Wi-Fi certification, which may be because of certification costs that must be paid for each certified device type.

Wi-Fi certification is provided for technology used in home networks, mobile phones, video games, and other devices that require wireless networking. It covers IEEE 802.11 standards, including 802.11a, 802.11b, 802.11g, and 802.11n.

Wi-Fi is supported by most personal computer operating systems, many game consoles, laptops, smartphones, printers, and other peripherals.