There are a couple similar but unique ways to connect to a REST API without basic authentication (username / password).

• Connect to a REST API with an API Key
• Connect to a REST API with an OAuth Bearer Token (this article)

Let's say there is an OAuth API that is configured to allow connections with a Bearer Token. You would first use the curl command to get your OAuth Bearer Token from the API.

curl
--request POST 
--url https://api.example.com/foo/bar/ 
--data '{ "Username": "john.doe", "Password": "itsasecret" }' 
--header "Content-Type: application/json" 

Something like this should be returned. In this example, "abc123" is the Bearer Token.

{
 "access_token":"abc123",
 "refresh_token":"T2w8o3xgET2K9Dh8abqnWQ==",
 "expires_in":31536000,
 "expires":1655380828,
 "token_type":"Bearer",
 "refresh_until":1655380828
}

You would then issue a command like this, using the Bearer Token.

curl 
--request GET 
--header "Authorization: Bearer abc123" 
--header "Accept: application/json" 
--url "https://api.example.com/foo/bar"