Lamar Smith, Chair of House Science Committee, Leaving Congress

I can't find information on likely Republican candidates for the TX-21 seat, but the Austin Chronicle has an article on Democratic candidates [0], one of whom is a 'tech entrepreneur':

Joseph Kopser (www.kopserforcongress.com), founder and president of Grayline (tech consultants), earlier established the RideScout transportation app, and continues to work as a tech entrepreneur. He emphasized this experience as well as his 20 years as an Army Ranger. He said his campaign will "avoid ideological extremes": "It's in the middle that we can find the progress to move our country forward."

[0]: https://www.austinchronicle.com/news/2017-06-09/campaign-201...