We actually do this at MobileWorks (mobileworks.com). There's an API that lets you get N minutes from N people filtered by demographic. Some folks use our Prem

We actually do this at MobileWorks (mobileworks.com). There's an API that lets you get N minutes from N people filtered by demographic. Some folks use our Premier product for on-demand testing set up by email -- they send test requests to premier@mobileworks.com. If you're looking for this more as a formal end-to-end service, you can take a look at our buddies at Rainforest (https://www.rainforestqa.com/ https://www.rainforestqa.com/). You can also look at services like uTest, though they're real pricey.