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.

• You can find the API key in the UTS ‘My Profile’ area after signing in. An API key remains active as long as the associated UTS account is active.
• To generate a new API key, click ‘Edit Profile’, select the ‘Generate new API Key’ checkbox, then scroll down and click ‘Save Profile’. Your new API key is now available for use.

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}}

We also offer an endpoint for validating API keys. If you have developed an application that integrates UMLS data and you need to determine whether a user is a UMLS licensee, you can use this endpoint to validate the user’s API key.

Make a request that includes both your API key (validatorApiKey) and the API key of the user of your application (apiKey). For example:

https://utslogin.nlm.nih.gov/validateUser?validatorApiKey=YOUR_API_KEY&apiKey=USER_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