Alexej Savreux, a 34-year-old in Kansas City, says he’s done all kinds of work over the years. He’s made fast-food sandwiches. He’s been a custodian and a junk-hauler. And he’s done technical sound work for live theater.

These days, though, his work is less hands-on: He’s an artificial intelligence trainer.

Savreux is part of a hidden army of contract workers who have been doing the behind-the-scenes labor of teaching AI systems how to analyze data so they can generate the kinds of text and images that have wowed the people using newly popular products like ChatGPT. To improve the accuracy of AI, he has labeled photos and made predictions about what text the apps should generate next.

The pay: $15 an hour and up, with no benefits.

Out of the limelight, Savreux and other contractors have spent countless hours in the past few years teaching OpenAI’s systems to give better responses in ChatGPT. Their feedback fills an urgent and endless need for the company and its AI competitors: providing streams of sentences, labels and other information that serve as training data.