One-way backup — watch a folder, upload what changes — is a weekend script. What Dropbox actually sells is silent, reliable two-way sync across every device you own, including the part where two people edit the same file offline and it doesn't eat one of the copies.
VIBE SCORE 91/100
The parts this build actually needs, each rated on its own — the average is the Vibe Score above.
| File uploads | 87 |
| User login | 92 |
| CRUD database | 95 |
Don't feel like building it? These are already made, open-source, and free.
Borderline. One-way backup — watch a folder, upload what changes — is a weekend script. What Dropbox actually sells is silent, reliable two-way sync across every device you own, including the part where two people edit the same file offline and it doesn't eat one of the copies.
Dropbox costs $11.99/mo (about $144/yr) as of 2026-08. That's what a working rebuild would save you.
True bi-directional sync with conflict resolution, across multiple devices possibly offline at once, is a much harder problem than the score above suggests — it's closer to a distributed-systems project than a CRUD app Selective sync, smart caching of large files, and OS-level integration on every platform is real, ongoing engineering Version history and file recovery after accidental deletion needs its own storage strategy, not an afterthought
Yes — Nextcloud, Syncthing are open-source options worth trying before you build your own. Details are in the standard parts section on this sheet.