Job posting claimed guaranteed response to all applicants within two days. A couple weeks after applying, I got an email notification for a HackerRank programming exercise, mentioning it was for StickerMule. I completed the exercise successfully and well within the time limit, and several weeks later got a template rejection email. At no point during this process did anyone from StickerMule personally contact me. I learned in the meantime that StickerMule's CEO has publicly supported extremist conservative conspiracy theories, so I'm glad I dodged a bullet there. Would not recommend applying.