Echoing with a similar bad experience although this might be their customer's (Mixpanel) fault. I applied to Mixpanel and they sent me a Triplebyte quiz. They bugged me a few times to fill it out and then promised to give me feedback "very quickly". I never heard back (I applied several months ago) and sent them 3 - 4 follow up emails.

I'm not sure if the fault lies with Triplebyte or Mixpanel but it was an overall shitty experience. To be asked to take out your time to complete a quiz (which can be automatically scored with an algorithm since its multiple choice) and then get radio silence is terrible. Even if it was Mixpanel's fault, they should ensure their partners actually follow up with interviewers. For example, I know that Hired (another platform) actually will ding an employer that doesn't respond to applicants.

Anyways, Mixpanel & Triplebyte are probably on my "never apply to again ever" list.