Nowhere in San Francisco is wealth disparity more prevalent than the Tenderloin.

In one of the grittiest downtown neighborhoods, homeless people sleep outside the offices of Uber, Microsoft, Twitter, Square, and other high-powered tech companies. Needles, garbage, and feces are found in concentrations comparable to some of the world's poorest slums. Drug dealers conduct business on the same blocks where tech workers buy venture-backed coffee.

It's clear that not everyone has benefitted from the economic gains of the tech boom.

In 2015, a formerly homeless man launched Code Tenderloin, a non-profit that provides job readiness training and basic coding skills to the city's homeless, formerly incarcerated, and disenfranchised populations — with the goal of putting them to work in the tech industry.

About half of the 300 people that Code Tenderloin has accepted into the program reported finding employment after graduation. An elite few have landed six-figure salaries as software engineers and customer service technicians at companies including Microsoft and LinkedIn.

I recently shadowed a cohort of Code Tenderloin participants. Here's what I learned.