The men were not identified by name.
Richards said she also had confronted a man earlier after he told her what she thought was a sexist joke at the conference.
"There is something about crushing a little kid's dream that gets me really angry," Richards wrote. "Women in technology need consistent messaging from birth through retirement they are welcome, competent and valued in the industry."
SendGrid was founded in 2009 and has developed a cloud-based email system, according to its website.
Thanawala reported from San Francisco.