When to introduce pacifier?

When did you introduce a pacifier to your baby?? And we’re they exclusively breastfed? With our first born we didn’t introduce a pacifier until she was 1 month old because we didn’t want her to get nipple confusion. But now we have a newborn and a toddler who nurses to sleep. So a pacifier for our newborn could come in handy but I just don’t know. She is and we plan to exclusively breastfeed her but will a pacifier ruin this?