Production halls are not controlled office environments. Coverage changes between machines, auditors interrupt walks and photos are much larger than simple answers. “Available on mobile” therefore does not mean an audit can survive real shopfloor conditions.
Separate drafts from submissions
An audit in progress is a mutable draft. A submitted audit is an immutable record. This boundary prevents temporary connectivity problems from marking partial information as complete and prevents later edits from changing historical results.
Autosave should persist small changes frequently and make clear whether information is local or synchronized. After a restart, the last consistent state must be recoverable.
Treat evidence as first-class data
Photos, annotations and voice recordings require a more robust queue than text answers. A draft must preserve their local connection to the question before upload is confirmed. Failed transfers need safe retry behavior that does not create duplicate files or lose relationships.
Compression is useful but must preserve the detail required for the audit decision. Define appropriate resolution, file types and retention periods for the actual use case.
Resolve conflicts deliberately
If several devices edit the same draft, a simple last-write-wins policy can overwrite information. Prefer clear ownership during execution or an explicit conflict flow. Once submitted, the audit instance should lock; necessary additions become new lifecycle events.
Test the offline behavior
MDN’s guidance on offline web application operation describes caches and background synchronization as building blocks, not a finished guarantee. Audit-specific scenarios include:
- Lose connectivity during a photo upload.
- Close the browser or app after several answers.
- Encounter full device storage.
- Reopen a draft after a long offline period.
- Prevent duplicate submission of an already accepted audit.
Technical logs must make failures diagnosable without copying sensitive audit answers or photos into operational logging. OWASP recommends designing logs around both security and privacy risk.
Offline capability is not a checkbox. It combines the data model, synchronization behavior, understandable status communication and tests that represent the actual working environment.