The Associate Software Engineer position is usually reserved for cases where we want to groom people into the Software Engineering career. Typically, these people might come from bootcamps where they know how to code but they can't work independently and require guidance to build a system.
Impact - System
A Software Engineer is usually capable of designing a system inside a team indepedently. All Software Engineers, whether they are junior or senior should have 2 core skills: Problem-Solving & Ability to learn.
Senior Software Engineer
Impact - Many systems in a team
A Senior Software Engineer typically designs many systems inside a team. He or she acts as a technical mentor within the team to guide other engineers on achieving technical excellence.
Impact - Team
An Engineering Lead is usually the final position before an engineer decides whether to invest 100% into the Manager Track or the Individual Contributor Track. It is common to find Engineering Leads owning all the delivery within a team, managing the engineers in their team and also act as their Software Architect.
Choose your career path: Manager or an Individual Contributor
A Staff Engineer role is the beginning of an engineering leadership role where you lead without direct management authority. Staff Software Engineers are commonly expected to act as an enabler for at least two teams and think about bigger problems across a team boundary.
Senior Staff Software Engineer
Impact - Entire business unit
These Senior Staff Engineers typically own a much bigger scope than the level below. In some companies, this could be an entire business unit consisting of multiple squads. They form best practices within their own business unit and are expected to collaborate with other business units.
Principal Software Engineer
Impact - Multiple business units or the company
Principal Software Engineers usually look after the architecture of multiple business units (or the whole company) in their portfolio, influencing engineers with strong persuasion and technical ability instead of pure authority. These engineers are usually trusted thought partners of senior leadership like CTOs.