Jacob Boyle graduated with $90 and a foam robot named MARCo. Seven years later it has talked with more than 15,000 people across 13 countries - and in a handful of cases, it called for help before things got worse.
Andrea Campos taught herself to code to fight her own depression. The chatbot she built now fields billions of late-night messages across Latin America - and is quietly testing where an app should stop and a doctor should start.