Snyder is the daughter of an American father and a Kenyan-born mother, Wayua Muasa.
Snyder was Director of Security Architecture at @stake and was a senior security strategist at Microsoft in the Security Engineering and Communications organization, most notably as security lead and signoff on Microsoft Windows XP Service Pack 2 and Windows Server 2003. After leaving Microsoft in 2005, she worked as a principal, founder, and CTO at Matasano Security. She joined Mozilla in September 2006.
On 10 December 2008, Snyder reported in the Mozilla Security blog that she would be leaving Mozilla Corporation at the end of the year. On 1 March 2010, Snyder began work at Apple Inc.