There's a special kind of academic pain that comes from learning about a deadline the week after it passed. Not the week before. The week after. You can't fix it. You can only mourn it, and the paper sits for six more months.
The fix is a conference deadline tracker app. iOS and Android versions of the genre do the same job, and the job is embarrassingly simple: remind you thirty days out, fourteen days out, and the morning of. Some sync with your calendar. Some filter by discipline. All of them beat the spreadsheet you swear you'll open.
So what do you actually compare? Five things. Alert timing, because a reminder the night before is a taunt, not a tool. Calendar sync, because a deadline that lives only in the app dies with the app. Venue coverage in your discipline, since a tracker full of biology conferences does nothing for a roboticist. Offline access, because conference wifi is where good intentions go to die. And a price you can defend to a department that funds nothing.
Here's my honest opinion. Most researchers don't need a feature-rich product. They need one alert that fires while there's still time to write. The fanciest lab deadline dashboard SaaS on earth can't rescue a paper that doesn't exist yet. Pick the tool whose alerts you'll actually keep turned on.
A mobile app for academic submission deadlines is the floor, not the ceiling. Pair it with the month-by-month calendar at confjournal.fyi, where conference submission deadlines are listed with dates, locations, and submission links, and you have a system instead of a wish.
And when the paper is finally done, confjournal.fyi runs paper formatting and submission checks so it actually gets in the door.