There are no strict definitions, different companies do it differently, have different requirements and role descriptions. Usually the path is junior -> no pref

There are no strict definitions, different companies do it differently, have different requirements and role descriptions. Usually the path is junior -> no prefix -> senior -> staff/lead -> principal (some companies have only the first 3/4, then only management above). One good source I found is gov.uk site: https://www.gov.uk/guidance/software-developer https://www.gov.uk/guidance/software-developer