fever

 Fever  was a self-hosted, proprietary feed reader that is no longer developed or sold as of 2016-12-24. It was a Google Reader-style feed reader written in PHP. It had a one-time fee of $30 and only worked on a single domain due to built-in DRM. It had some interesting "sparks and trends" features which de-duped articles in order to create a "fever" view of links that many articles link to.

The FeverAPI is still used in many feed readers as a sync endpoint. It is available as an option in Unread on iOS, ReadKit on macOS and Reeder on Mac and iOS, for example.

For use as a syncing backend, fever is supported in some self-hosted RSS readers/aggregators like miniflux, stringer, RssMonster, and as a plugin for tt-rss. This allows the user to avail of the fever-api reading capability of the above apps.

People who use fever

 * - I used to run fever until malformed feeds hosed the backend DB. It has a single developer, has a non-open source license, contains many bugs and never gets updated. Do not recommend especially with all the other options these days.