If you're looking for a balance of privacy, convenience, and a friendly backpacker vibe, Social House is the perfect place for your Istanbul stay.
The hosts are amazing and full of useful advice and genuine recommendations. The location is great with easy access to Sultanahment sights and to a tram line. This does mean the area is noisy during the day, but quiets down overnight. The hostel set up makes meeting people easy, but the private rooms mean you can shut out the world. The kitchen is well equipped and the shared girls' bathroom is always spotless, can't vouch for the men's though ;). The rooftop is super for a late-night chill or early morning yoga session.
Special shout out to Ridvan and Mustafa. Thanks for looking after us.