> We were calling their API, and the app was clearly just waiting for results, which sometimes would take half a minute. Clearly to whom? You shouldn’t expect

> We were calling their API, and the app was clearly just waiting for results, which sometimes would take half a minute. Clearly to whom? You shouldn’t expect your users to know that your client’s API may be slow. > I added a progress bar that started at 5% went +10% every second till 65% That’s bad. If you don’t have a reasonable estimate for how long something will take, you should use an indeterminate progress bar. https://m2.material.io/components/progress-indicators#usage https://m2.material.io/components/progress-indicators#usage: “Determinate and indeterminate Progress indicators may be determinate or indeterminate: Determinate indicators Determinate indicators display how long a process will take. They should be used when the process completion rate can be detected. Indeterminate indicators Indeterminate indicators express an unspecified amount of wait time. They should be used when progress isn’t detectable, or if it’s not necessary to indicate how long an activity will take.” For this case, I would wait a second or so to see whether an answer returns rapidly, then pop up an indeterminate progress bar and keep it up for at least a second, even if the reply comes sooner.