Application Program Interfaces (APIs) are available to users to retrieve data from several drug information sources, including RxNorm, MED-RT and RxTerms. Currently there are five APIs available:

• RxNorm API for retrieving data from the RxNorm data set.
• RxNorm Prescribable API for retrieving data from the RxNorm Current Prescribable Content.
• RxTerms API for retrieving data for the RxTerms data set.
  
• RxClass API for retrieving drug classes and drug members from a number of different drug class types.
  
• Drug Interaction API for accessing drug-drug interactions.
  

APIs are available as RESTful web services. A RESTful web service is a web service implemented using HTTP and the principles of Representative State Transfer (REST). The RESTful web services can return the data in XML or JSON. (SOAP access to the APIs was deprecated in July 2019 and terminated in January 2020.)

The APIs are also available as part of RxNav-in-a-Box, which provides users with a locally-installable version of RxNav, RxClass and the APIs.

The API resources can also be used interactively or in batch mode with RxMix.

We invite you to develop computer and mobile applications using National Library of Medicine (NLM) resources. We request that any application that makes use of NLM data include the following statement:

"This product uses publicly available data from the U.S. National Library of Medicine (NLM), National Institutes of Health, Department of Health and Human Services; NLM is not responsible for the product and does not endorse or recommend this or any other product."