Ruby-Doc.org contains documentation, API references, standard library guides, and version-specific resources for all classes, methods, and modules and is very useful for Ruby developers.
Ruby-Doc.org is popular because of its documentation of Ruby programming language, including language reference, standard library documentation, API documentation etc. It is useful if you are learning Ruby or need to know more about specific class and method.
Before making a choice, Ruby-Doc.org is a free documentation provider so promo codes are not applicable here. It is useful because it allows developers to get access to the documentation without subscribing for paid services.
Usually, yes — you can use it for free via web browser. It is great tool for students, self-taught and professional developers who are looking for documentation quickly.
Using free documentation can help you save money on purchasing paid books or attending paid training programs when learning some specific Ruby features. Beginners might need to attend some courses, but Ruby-Doc is great for reference purposes.
In case, some users find that Ruby-Doc.org might contain documentation for multiple versions of Ruby and libraries. You should check if you are reading right version of documentation for your project.
It can help beginners, but it is a reference tool rather than training course. Newbies might benefit from attending some training courses and exercises, but Ruby-Doc.org is great for reference.
Information about pricing might differ, but Ruby-Doc is a Ruby documentation, so it might not include Rails documentation. For Rails documentation, official Rails documentation might be a better option.