Building Flutter apps for people with no signal

Most mobile apps assume connectivity and degrade badly without it. If your users are drivers, warehouse staff or nurses, that assumption is wrong for a meaningful share of their working day.

Local first, sync second

Write to a local database, always. The network layer's job is to drain a queue in the background, not to be in the path of anything a user does. A driver capturing a signature should never see a spinner, and should never care whether the request succeeded.

Decide your conflict rules before you need them

Two devices will eventually edit the same record offline. Last-write-wins is a decision, not a default — make it deliberately, and write down who wins. On a retail POS we built, the rule is that the till serving a physical customer beats the website every time. That is a business decision, not a technical one.

Compress for a bad uplink

Photographs are the usual killer. Resize and compress on device before queuing. A 4MB proof-of-delivery photo on a 2G connection in a basement is a sync that never completes and a battery that does not last the shift.