SAN FRANCISCO — Ruchi Sanghvi was the first female engineer at Facebook, where she helped create the news feed that now serves as the primary window into the world’s largest social network. Then she built a start-up of her own and sold it to another rising Silicon Valley company, Dropbox, becoming one of its first female executives. But as she left Dropbox in 2014, she didn’t know what she would do next.

At 32, she wanted a better way of deciding where her career would go. She wanted an environment where she could freely explore new ideas among her peers without feeling the pressure to start another project immediately.

As the months passed, she never quite found that kind of personal think tank, but she came to realize that many old friends and colleagues felt much the same way. Her next project became an effort to help people find their next project.

The result is South Park Commons. Housed in an old townhouse on the oval park at the heart of the San Francisco tech scene, the Commons is a selected community of entrepreneurs, engineers, researchers and others. Ms. Sanghvi describes it as tech’s answer to the Bloomsbury Set or Benjamin Franklin’s Junto club, a means of shaping new ideas through conversation and shared experience.