Few things are as frustrating as watching a large upload hit 90% and then fail, forcing you to start over from zero. This happens more often than it should, and it's rarely about the file itself — it's about how the upload is being sent over the network.
The problem with sending a file all at once
Most simple upload systems send a file as one continuous stream. If the connection drops for even a second — a wobbly Wi-Fi signal, a phone switching from Wi-Fi to mobile data, a router hiccup — the whole upload fails and you're back to square one. The bigger the file, the more painful that is.
How chunked uploads solve it
A chunked (or resumable) upload breaks the file into smaller pieces before sending them, rather than pushing the whole file in one go. Each chunk is uploaded and confirmed separately, so if the connection drops mid-upload, only the current chunk needs to be retried — not the entire file.
This makes a real difference on unreliable connections, and it's especially useful on lower-powered devices, since smaller chunks are easier to process without straining memory or CPU.
What this means for you
- Fewer full restarts — a dropped connection costs you seconds, not the whole upload.
- More reliable large-file transfers — useful for videos, design files, or datasets that would otherwise be risky to send over spotty networks.
- Better behavior on weaker devices — smaller chunks mean less strain on limited hardware, so uploads stay smooth instead of freezing up.
If you regularly upload large files from places with unreliable internet — a train, a coworking space, a phone hotspot — a service with chunked uploads will save you a lot of repeated attempts.