NLM logo

We welcome your feedback on our customer service form. Please use "UMLS REST API feedback" in your subject line.

Check out the Postman sample collection to help you get started using the UMLS REST API.

API Terms of Service

User Authentication

The UMLS REST API requires a UMLS account for the authentication described below. If you do not have a UMLS account, you may apply for a license on the UMLS Terminology Services (UTS) website.

Step 1: Get your API key from your UTS profile.

Step 2: Append your API key to a data request.

For example, https://uts-ws.nlm.nih.gov/rest/content/current/CUI/C0009044?apiKey={{YOUR_API_KEY}}


Note: AccessGUDID users can now use the API Key authentication method. For AccessGUDID users that have previously implemented Ticket-Granting Tickets and Service Tickets for authentication, please refer to this documentation:

Ticket-Granting Ticket and Service Ticket Documentation