Change.org Senior Software Engineer interview questions

Recruiter contacted me and scheduled a technical phone screen with their principal engineer. After 1st technical phone screen, another technical phone interview was scheduled. This involved 2 programs. Then onsite interview in their SF office. 6 back-2-back interviews (same as most of SF technical interviews at software companies). Recruiter was very nice and communicative during whole process. Not sure what happened, after reference checks, they decided to not proceed further with me. I am sure it was because of budgeting concerns.