This question is probably aimed at beginners, because once you "get" programming, learning new languages will never be a problem. Reaching that stage, however, might take years. There isn't a single course or book that covers this field in its entirety.

Programming as a whole is a deep subject, with different languages serving different markets or functionalities. Your goal as a programmer is to learn how to deliver software, and in order to do that, I personally find that building applications is the optimal choice.

The core differentiator between programming languages is the syntax and input/output manipulation. If you take 10 different courses in 10 different languages you will probably end up knowing is how to handle forms and upload images in 10 different ways.
You will never learn how to validate, securely store or send the data. You will never learn properly structure your software according to an architectural pattern.

To summarize, if you want to become a programmer, then go ahead and BUILD, or read books.

The best API depends entirely on your data source, your budget, and your needs.

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