I just looked at Stripe's job page and noticed they don't advertise any positions as "Senior" nor do they appear to list 'years required' in any of their listings. Definitely a fresh take, and I hope it actually does yield better applicants and results!
Apparently, everyone has the "same" title - levels are only reflected in your pay band.
By the way, this goes almost all-the-way-up.
Even people who were former VPs at Google often have the title "Engineering Manager". Sure, they mostly manage other EMs, but it's hard to precisely tell who is super senior and who isn't.
This actually plays out nicely, as it encourages everyone to default to each other as equals. Later on you'll hear things like "did you know that person built the entire first version of Atlas by themselves?" only to realize they are, in fact, very experienced. :]