Peter Bauer co-founded Mimecast in 2003 with Neil Murray. The company sold email management as a cloud service at a time when most businesses ran their own mail servers, and it later widened into archiving and security.
In June 2010 Mimecast hired Dr Nathaniel Borenstein, a co-creator of the MIME email standard, as chief scientist. The company listed on Nasdaq in November 2015 under the ticker MIME.
In January 2021 Mimecast disclosed that a security certificate had been compromised. Investigators suspected a link to the SolarWinds attackers, which was not confirmed. In May 2022 Permira bought the company for about $5.8 billion.
In January 2024 Marc van Zadelhoff replaced Bauer as CEO. Mimecast is headquartered in London, with its North American base in Lexington, Massachusetts.