To obtain an API Key through your NCBI account, follow these steps:

• Sign in to your NCBI account.
  • If you do not yet have an account, bear in mind that NCBI no longer supports direct account creation, but you can still acquire an account through 3rd party sign-in options. 
  • Note furthermore that existing accounts, if originally created directly at NCBI, must transition to 3rd-party sign-in by June 2022. (See the FAQ page for further information.)
• Once signed in, access your account's settings by clicking on your user name which is displayed in the top right corner of any NCBI page.
• Scroll down the page to the section entitled API Key Management.
• Click the Create an API Key button, which will generate a key (unique sequence of characters) displayed in the API Key Management box.

You can then copy the API key and enter it as an environmental variable on the command line, for example, or as a data field at a service’s API. For instance, an EUtilities einfo request (entered as a browser-readable URL) will simply append the API key at the end of the link:
 

Specific procedures and further guidelines for invoking API keys can be found in the documentation for EUtils services; additional procedural updates for applying Datasets API keys are in progress.