Most likely, your offer is just too low. Senior developers almost by definition have experience with their own market value and plenty of offers from their net

Most likely, your offer is just too low. Senior developers almost by definition have experience with their own market value and plenty of offers from their network. If you're going to offer less than what a friend's company offers, you'll need to have insanely amazing tech to compensate. And I'm always assuming that companies pay badly if they are cagey about naming the salary. I mean you also didn't say if you were offering $100k or $300k annually.