I've been working with Zillow's Mortgage API - specifically GetMonthlyPayments, and it appears to have just gone down, along with all associated documentation and URLs (http://www.zillow.com/howto/api/GetMonthlyPayments.htm). Anyone have any insight into what's happened or why? No response from Zillow customer support.
I have a contact at Zillow and asked them what happened to their mortgage calculator.
Response: "They killed it. I don't know why." And an apology about there being no communications around this.