Is A-B testing process necessarily happens before developing the feature, or we could do it as an on
Is A-B testing process necessarily happens before developing the feature, or we could do it as an ongoing process during the feature life?
In response to your question, it could go either way, but more often than not, A/B testing is carried out on existing features to enhance their performance. This is closely tied to the fact that feature development usually takes less time than its entire lifecycle on production, where it is already available to users.
In fact, a third option exists, as A/B testing is sometimes conducted even before active development begins. For instance, imagine you want to start your own business; let's say you're skilled in sewing dresses and building beds. You like both activities, but you have to choose because it requires purchasing specific equipment.
To test which business would be more profitable, you could launch two advertising campaigns, perhaps on Facebook, leading to two different landing pages where customers can submit inquiries. By investing a small amount in advertising and tallying the number of "orders", you can conduct a kind of A/B test and compare the potential profits (or, even better, the return on investment) of each business in the early stages.
Based on the above, experiments (A/B tests) can be conducted at various stages.