On a cold February morning, Betches Media, the millennial and Gen Z women’s humor company best known for its Instagram memes, was celebrating its 13th birthday, which its three co-founders had gleefully named its “betch mitzvah.”

There would be a toast and cake for its employees — there are 63 full-time — at the company’s Flatiron district office but the occasion was mostly an inside joke, said Sami Sage, its chief creative officer.

“There’s no Torah reading,” Jordana Abraham, the chief comedy officer, deadpanned.

As far as coming-of-age tales go, Betches has an upbeat one in a digital media landscape without many. The company, which was early to the phenomenon of viral content as a foundation for digital media companies, never took on outside investment, unlike most of its peers. Now, it is reaping the benefits of that approach.

Ms. Abraham, 34, Ms. Sage and the chief executive, Aleen Dreksler, both 35, have known one another since they were fifth graders in the well-to-do Long Island suburb of Roslyn. They started an anonymous humor blog, called “Betches Love This Site,” while they were seniors, roommates and sorority sisters at Cornell University in 2011. It satirized their affluent social cohort, going heavy on shock value. (A guide to drinking recommended shots, preferably of vodka, with the aim of blacking out; recommended diets included anorexia.)

That blog, which later dropped “Site” from its name, turned into a book deal, then a website, then eventually a media company anchored by a dozen or so Instagram accounts. The company’s main profile, which has 9.2 million followers, posts funny short-form videos and other jokes from around the web that are intended to be relatable enough to DM to a friend. (Its bio reads: “POV: you’re the funniest friend in your group chat.”) One of the site’s greatest hits is “American Girl Dolls Ranked By Betchiness” and its Instagram account recently received a flurry of coverage when Taylor Swift “liked” a post of a meme ranking her exes.

Christian Tom, director of the White House’s office of digital strategy, recently said @BetchesNews was among the Instagram accounts the White House used to reach millennials. Betches News visited the White House in March for a round table with Vice President Kamala Harris.