This post was updated on February 2, 2017.
If you regularly use the E-utilities API, we have important news for you: NCBI is now providing API keys for the E-utilities! After May 1, 2018, NCBI will limit your access to the E-utilities unless you have one of these keys. Obtaining an API key is quick, and simple, and will allow you to access NCBI data faster. If you don’t have an API key, E-utilities will still work, but you may be limited to fewer requests than allowed with an API key.
What is an API key?
An API key is a unique string that you include in your HTTP requests that identifies you to NCBI servers. Think of the API key as a ‘turbocharger’ that lets you get more data, faster, from NCBI.