Curl best practice for API calls? Protecting sensitive data like API keys

So there is no need to specifically use single_service() in my libraries that use curl requests? The options for curl requests passed to the constructor are usually not shared?

No! You should use single_service() to protect sensitive data.

The options for curl requests passed to the constructor are always shared.

The options to the request() method are not shared.
See https://www.codeigniter.com/user_guide/l...ml#headers
In the sample code, the headers are not shared in the next request.

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