Weights & Biases, a startup building development tools for machine learning, has raised $15 million in its second round of funding. The company was started by CrowdFlower founders Lukas Biewald and Chris van Pelt, along with former Google engineer Shawn Lewis. When Weights & Biases launched last year, Biewald (who I've known since college) said he wanted to create the tools needed to "build and deploy great deep learning models." Its initial product allows companies to monitor those models as they develop and train them. "When people build machine learning models they need to track everything that happens -- the code that went into the model, the hyperparameters that go into the model and then basically how well the model does," Biewald told me this week.

Machine learning is one of those buzzwords that nearly every tech company likes to throw around nowadays -- but according to Lukas Biewald, it represents a genuinely new approach to programming. "Software has eaten a lot of the world, and machine learning is eating software," Biewald said. In his view, there are "fundamental" differences between the two approaches: "One important difference is if all you have is the code you used to train the program, you don't really know what happened … If I had all the code that was used to train a self-driving car algorithm but I don't have the data, I don't know what went down." Along with Chris Van Pelt, Biewald previously founded CrowdFlower (now known as Figure Eight), which launched nearly a decade ago at the TechCrunch 50 conference, and which has created tools for training artificial intelligence. Biewald (who I've known since college) and Van Pelt, plus former Google engineer Shawn Lewis, have now started a new company called Weights and Biases to build new tools for machine learning developers.