A distributed search system, such as Solr, requires remote service invocations to send and receive data across a network. Clients without appropriate APIs will be exposed to the complexity of dealing with low-level details of the communication protocol.

Since Solr provides all core services through HTTP, a lot of client libraries have been developed to hide that complexity. Regardless of the concrete binding, a client library encapsulates the low-level details of client-server communication and provides a uniform service interface for clients.

In this chapter, we focused on the Solr client APIs, specifically on the official Java binding called Solrj, its main features, and the main classes involved in index and query operations.

We briefly described and listed some other popular bindings that have been developed on top of the Solr HTTP services.

In the next chapter, we will return to the server side to describe how to fine-tune and manage a Solr instance.