Note that you cannot request or view your API keys without first logging into your fredaccount.stlouisfed.org user account.
The API key is set using the api_key variable, a 32 character lower-cased alpha-numeric string.
Below is an example HTTP GET request:
https://api.stlouisfed.org/fred/series/search?api_key=abcdefghijklmnopqrstuvwxyz123456&search_text=canada
Note that API key 'abcdefghijklmnopqrstuvwxyz123456' is for demonstration purposes only. Use one of your registered API keys instead.