BibSonomy provides an API (Application Programming Interface) which other software programs can use to access the services and resources provided by BibSonomy. It is build on the REST (Representational State Transfer) architecture style and enables programs to post data (for example creating a new user), read data (for example getting the publications or tags of a user), updating or deleting data (for example one's own entries).

Recently, a new parameter for reading a user's tags was added. The parameter enables an alphabetical or frequency-based ordering of tags.