I recently shut down my startup as well, and definitely feel I learned a lot from the experience. My startup failed because we did not seek customer validation

I recently shut down my startup as well, and definitely feel I learned a lot from the experience. My startup failed because we did not seek customer validation until our product was already built (after months of development). And at that point we realized we had built a product that nobody wanted. From now on I will not start building a product unless I already have customers who want/need it!