By law. H1b requires the wages to be greater than the prevailing wage for similar positions in the region. They are published by DoL: https://flag.dol.gov/wage-data/wage-search
For this kind of experience, you'd be looking for level 2 _minimum_ and likely level 3. For King County in WA it's right now $149240 and $180710 respectively. Level 4 wage is $212202, btw.
The H1B requirements are even higher, but also WA state law requires software developer salaries to be 3.5 x minimum wage x 52 weeks per year. Currently, that is $124k+, because minimum wage is $17.13 per hour.
The lowest allowed limit for such a job is around $140k in areas like Seattle.