Usually babies don't sleep through the night without a feeding until around 5 or 6 months of age.
However some babies may sleep through the night without a feeding by 3 to 4 months of age but if a baby does need a feeding during the night they'll usually wake you up in the middle of the night by crying and letting you know that they're hungry.
Once the baby reaches 6 months of age and beyond they can almost always sleep overnight without needing a feeding so you can get some rest.
But be prepared to lose sleep for the first 6 months of the babies life because they will usually cry a lot during the night whether they need a feeding or not because sometimes they might need a diaper change, cuddling etc.