On the web, the termrouter can refer to different concepts depending on the context:

• For the network layer, a router is a networking device that decides where to directdata packets.

• For asingle-page application (SPA) in the application layer, a router is a library that decides what web page is presented by a givenURL. This middleware module is used for all URL functions, as these are given a path to a file that is rendered to open the next page.

  The concept of routing in SPAs has evolved significantly over the years. See thehash routing glossary entry to learn more.

• In the implementation of anAPI in a service layer, a router is a software component that parses a request and directs or routes the request to various handlers within a program. The router code usually accepts a response from the handler and facilitates its return to the requester.

See also

• For the network layer context, seeRouter (computing) on Wikipedia.
• In the application layer context, most of the popular SPA frameworks include built-in routing libraries, such as:
  • Angular router
  • React router
  • Vue router