Ever noticed how insanely fast Reels upload? A multi-minute video sometimes finishes almost the moment you tap “Post.” The secret is that Instagram starts uploading the file the second you pick it on your phone. While you’re busy editing the caption, thumbnail, tags, or location, it’s already working in the background. By the time you’re done, so is Instagram — and the Reel goes live instantly.
This little hack has been in play since Instagram’s early days, when they used it for tiny 512×512 photos. You’d write a caption, while Instagram quietly handled the heavy lifting.
Even funnier — they borrowed the original idea from Gmail, which began pre-loading user data (like emails) as soon as you typed your username. Why? Because if someone enters their email, odds are they’ll also enter their password and want to see their inbox. And if someone picks a photo or video, they’ll almost certainly upload it. Sure, sometimes you’ll waste a bit of work — but the odds are low.
What I love most is that we’ve gone from text (emails), to photos (hundreds of KB), to videos (tens of MB) — and this tiny UX trick has stayed the same. Now I’m just waiting for the day when I step into a teleporter and they’ll start assembling me before I’ve even left the room.