I am writing to a company to ask about one of its software products.
my question is:
What programming languages and techniques have product_name been developed by?
am i using the have been and by correctly?
No: both have been and by are used incorrectly here.
Have been is grammatically incorrect. The fact that the entity you are primarily interested in and that you are asking about is programming languages and techniques does not make it the subject of your sentence. That entity is syntactically the object of the preposition by; the syntactic subject of the sentence is product_name, as you may see by recasting this sentence in indicative mood:
Product_name has been developed ...
Have been is also pragmatically incorrect. A perfect construction is ordinarily used to indicate a state arising out of a prior action; the action itself is of secondary interest. For instance, you might say that product_name has been developed in the context of announcing its release to market or pointing out the new features it makes available. But if your focus is on the action itself, the process, as it is in this case, a simple past is preferable:
Product_name was developed ...
By is semantically incorrect. In a passive sentence, a preposition clause headed by by names the ‘agent’ of the action, the person or group or organization which performs the action.
Product_name was developed by company-name...
To name the means employed, we typically use a preposition phrase headed by with or using:
Product_name was developed with Ruby on Rails.
These would be ‘correct’ versions of your question:
What programming languages and techniques was product_name developed with? OR, if you want to avoid the stranded preposition at the end of the sentence,
With what programming languages and techniques was product_name developed?
But there are other ways of asking the same thing; for instance
What programming languages and techniques were used in developing product_name?