Salary aggregators do not measure the same thing. Glassdoor and Levels.fyi rely on self-reported submissions, which skew toward people willing to report and toward certain employers. Job-board estimates (Indeed, ZipRecruiter) blend posted ranges with model-derived estimates. Career-guide pages (Coursera) often re-publish figures from those same aggregators.
The practical consequences: (1) ranges are wide and sources disagree — a 25th-to-75th-percentile band of roughly $102,000 to $166,000 on one source and $47,000 to $88,000 on another is normal, not a contradiction, because the underlying samples differ. (2) 'Total compensation' at tech companies includes equity and bonus, which can dwarf base salary, so a base-salary number and a total-comp number are not comparable. (3) 'Prompt engineer' is a young, loosely-defined title, so the same work appears under several job names (see the related-titles section).
So read every figure below as 'this is what this named source currently reports,' not 'this is what the job pays.' Where we cite a number, we name the source and link it so you can check whether it has moved.