Called "Flex," Amazon uses AI to determine how many drivers are needed for deliveries. The app, installed on drivers' smartphones, measures whether they delivered packages on time and followed customers' special requests. 

If a driver misses the mark, they are subjected to an automatic firing. 

That's exactly what happened to Stephen Normandin, 63, an Army veteran who Flex recently fired. He said algorithms tracked his every move as he delivered packages around the Phoenix Metropolitan Area. 

Normandin said Amazon unfairly punished him for things way beyond his control - such as locked apartment complexes. He said every job he's "given 110%," but the algorithm failed to see external factors that may affect deliveries. 

"This really upset me because we're talking about my reputation. They say I didn't do the job when I know damn well I did," he said. 

At the world's largest e-commerce retailer, algorithms are the boss, hiring and firing and monitoring hundreds of thousands of workers with hardly any human oversight. 

Flex began operations in 2015 as a way for Amazon to get its packages out the same day to regional customers. Here's more from Bloomberg: 

But the moment they sign on, Flex drivers discover algorithms are monitoring their every move. Did they get to the delivery station when they said they would? Did they complete their route in the prescribed window? Did they leave a package in full view of porch pirates instead of hidden behind a planter as requested? Amazon algorithms scan the gusher of incoming data for performance patterns and decide which drivers get more routes and which are deactivated. Human feedback is rare. Drivers occasionally receive automated emails, but mostly they're left to obsess about their ratings, which include four categories: Fantastic, Great, Fair, or At Risk. -Bloomberg